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2.5L Performance Upgrades

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Old 08-23-2006, 11:10 PM   #1
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2.5L Performance Upgrades

Looking for some decent performance upgrades for my Duke that are not too difficult to perform. Good cam to exchange and intake, perhaps? Let me know of anything that will be worth my time and money. Thanks!
Old 08-23-2006, 11:15 PM   #2
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Re: 2.5L Performance Upgrades

Quote: Originally Posted by fatmanmitch
Looking for some decent performance upgrades for my Duke that are not too difficult to perform. Good cam to exchange and intake, perhaps? Let me know of anything that will be worth my time and money. Thanks!




there are what seems a few hundred thread's like this one already, please search before starting a new one.
Old 08-24-2006, 01:25 AM   #3
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Re: 2.5L Performance Upgrades

scott, DOES have a point. however, there is hardly anything u can do to this engine that will be worth ur time and money. You can spend approx. 1000.00 (if u do all the work urself), and get the engine rebuilt using a performance RV cam, aluminum timing gear, hi-flow oil pump, upgraded rockers, hyperutectic pistons, molley rings, and it'll give u MAYBE an extra 10-15 HP. then there is also the option of putting in a reuseable air filter of ur choice (ie, K&N). putting in a LuK clutch will allow your clutch to take a beating while ur hammering through all those gears. Umm... and this my friend is about it. the 2.5L doesnt have a special bolt on intake. some people believe a new performance header makes a difference, but it'll only make a difference if you put the money into a good exhaust too.
sorry to burst ur bubble. it'd be more worth ur time and money to buy a 350 and put that in
Old 08-24-2006, 01:26 AM   #4
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Re: 2.5L Performance Upgrades

scott, DOES have a point. however, there is hardly anything u can do to this engine that will be worth ur time and money. You can spend approx. 1000.00 (if u do all the work urself), and get the engine rebuilt using a performance RV cam, aluminum timing gear, hi-flow oil pump, upgraded rockers, hyperutectic pistons, molley rings, and it'll give u MAYBE an extra 10-15 HP. then there is also the option of putting in a reuseable air filter of ur choice (ie, K&N). putting in a LuK clutch will allow your clutch to take a beating while ur hammering through all those gears. Umm... and this my friend is about it. the 2.5L doesnt have a special bolt on intake. some people believe a new performance header makes a difference, but it'll only make a difference if you put the money into a good exhaust too.
sorry to burst ur bubble. it'd be more worth ur time and money to buy a 350 and put that in
Old 08-24-2006, 04:53 AM   #5
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Re: 2.5L Performance Upgrades

I had a 2.5 a while back, and had the head shaved some(don't know how much, was done when i got it), and some custom exhaust without a cat, it ran pretty decent, outran a few fullsize v-8 trucks with it, got about 25 mpg out of it.
Old 08-24-2006, 07:12 PM   #6
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Re: 2.5L Performance Upgrades

Woah double post lady explicit, lol, only jokes
Old 08-24-2006, 10:28 PM   #7
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Re: 2.5L Performance Upgrades

God Damnit, I didn't post my question to get told put a 350 in.

Anyway--do they make any chips or EPROMs or anything to enhance TBI-tuning?
Old 08-24-2006, 10:34 PM   #8
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Re: 2.5L Performance Upgrades

Quote: Originally Posted by ladyexplicit
scott, DOES have a point. however, there is hardly anything u can do to this engine that will be worth ur time and money. You can spend approx. 1000.00 (if u do all the work urself), and get the engine rebuilt using a performance RV cam, aluminum timing gear, hi-flow oil pump, upgraded rockers, hyperutectic pistons, molley rings, and it'll give u MAYBE an extra 10-15 HP. then there is also the option of putting in a reuseable air filter of ur choice (ie, K&N). putting in a LuK clutch will allow your clutch to take a beating while ur hammering through all those gears. Umm... and this my friend is about it. the 2.5L doesnt have a special bolt on intake. some people believe a new performance header makes a difference, but it'll only make a difference if you put the money into a good exhaust too.
sorry to burst ur bubble. it'd be more worth ur time and money to buy a 350 and put that in
I agree, but if you are really set on getting nominal HP increases an intake and exhaust would be my first two steps.
Old 08-25-2006, 02:28 AM   #9
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Re: 2.5L Performance Upgrades

i dont know the name of the guy, but there is someone on ebay who can burn chips......

seriously... the 2.5L is such a waste of time to get power out of. ive put so much money into my engine, transmission, and clutch.. and i MAYBE have gained 25 HP out of it ALL!! whoo hoo... almost 4g's down the hole!!!!!

i know im being really negative.. and u probably dont like hearing it.. but a 350 is seriously the way to go.
Old 08-25-2006, 12:36 PM   #10
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Re: 2.5L Performance Upgrades

why? it's an outdated 4 banger. keep it stock and drive it till it breaks. then drop a totaly diff engine in.
Old 08-25-2006, 05:00 PM   #11
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Re: 2.5L Performance Upgrades

Quote: Originally Posted by ladyexplicit
i dont know the name of the guy, but there is someone on ebay who can burn chips......

seriously... the 2.5L is such a waste of time to get power out of. ive put so much money into my engine, transmission, and clutch.. and i MAYBE have gained 25 HP out of it ALL!! whoo hoo... almost 4g's down the hole!!!!!

i know im being really negative.. and u probably dont like hearing it.. but a 350 is seriously the way to go.

sad to say.. but you're right. Unless you want to spend THOUSANDS to get up to the 170hp mark and still get walked by any half decent car, do some sort of motor swap... hell why not a newer 3.4L?... I can guaruntee you will get about the same mileage, a hell of a lot more power, and much easier/cheaper to make a good hp gain.

And ladt explicit... if you haven't done it already, get your heads worked bigtime... if you only gained about 25hp then it sounds like somethings holding you back.
Old 08-25-2006, 10:24 PM   #12
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Re: 2.5L Performance Upgrades

Do you people not get it? I DONT WANT TO DO A SWAP RIGHT NOW. It isnt hard to comprehend that, I already said it and I am not going to say it again. If the only input you've got is swap in a different motor, ignore my thread, I am WELL AWARE that is the "best" way for more HP. I am looking for things to do until I can get enough time to do the V8 (Thatll be another year or so down the line)
Old 08-26-2006, 09:39 AM   #13
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Re: 2.5L Performance Upgrades

we are all just trying to save you from wasteing your time and money, but since you already know where we all stand on this subject, a cold air intake, since no company makes one youll have to fab it up yourself, exhaust header cliffordperformace makes that, any kind of muffler eg. flowmaster, maganflow, im sure they do make a chip for the computer, check with tbichips.com, try some synetchic oil, trans, and rear end fluids maybe?, the rest of the tricks for getting alittle more power would be, switching to a carb, or ripping the engine apart, and have some head work done, put in a nice camshaft, bore the cylinders out, good luck with your 2.5
Old 08-28-2006, 12:46 AM   #14
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Re: 2.5L Performance Upgrades

Did u not read my first post???

I told you everything you'd need to do. Have u at least done ANY searches on the 2.5L section?? If u have, you'll see alot of questions about a 3.0L crank. There are no 'bolt on' accessories for the 2.5L that will boost you any power. Any power will have to be acheived through re-building the engine. THIS is why we said, if ur going to try and get more HP through ur engine, you're going to have to rebuild it. If ur not up for that... then swap it. Cause your not going to get any other power out of it really any other way.

And SnafuPimp, that 25HP was just a guess I haven't dyno'ed nothing yet cause everything keeps breaking on me!!! haha. First I had clutch problems, then i had hydrolic clutch problems, now i have transmission bearing problems. Next to go will probably be the rear end from all the burn outs. hahaha
Old 08-28-2006, 02:24 AM   #15
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Re: 2.5L Performance Upgrades

Quote: Originally Posted by fatmanmitch
Do you people not get it? I DONT WANT TO DO A SWAP RIGHT NOW. It isnt hard to comprehend that, I already said it and I am not going to say it again. If the only input you've got is swap in a different motor, ignore my thread, I am WELL AWARE that is the "best" way for more HP. I am looking for things to do until I can get enough time to do the V8 (Thatll be another year or so down the line)

well heres what ive done with mine. I have put a new injector in, flipped the filter lid, put 2.5 inch pipe to a high flow cat back to a flowmaster delta 40. New clutch, short shifter, and regular maintnece and i can chirp first second an third. Mine is decent for what it is, and im happy with it. I beat on it almost everyday, 4-5k shifts and such atleast once a day. Another thing you can do is pull your intake off clean everything real good, make sure theres not alot of carbon building up and make sure everything is flowing good. As you problably know already its not a high revving motor. Yes, grantid the best answer for big HP is put a v8 in it, but if your in any situation like me, you dont have the time nor the place to do it. If you have any more questions about the duke hit me a PM, as for a 350 being the way to go, that may not always be the case. depending on what somone whats.You can build one high reving 289 by destroking it a smidge, or go my route and want a turboed 305. And dont tell me its a waste of my time because its already done and ive driven it, and it holds the 15 lbs of boost quite nicley, and is putting down well over 300 hp at the rear wheels, which is more than what i need.

Last edited by lowxpectationz20; 08-28-2006 at 02:32 AM.
Old 08-28-2006, 07:24 AM   #16
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Re: 2.5L Performance Upgrades

Sweet Setup.
Old 08-28-2006, 02:18 PM   #17
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Re: 2.5L Performance Upgrades

I gained a good bit swapping to a carb
Old 08-31-2006, 06:26 PM   #18
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Re: 2.5L Performance Upgrades

well...since you seem like an intelligent guy who will be a productive member of the S community...I'll let you in on a secret...you will be the FIRST one to know this trick without first having gone through the initiation process and knowing the secret handshake...

stickers....seriously. lots of them. Type R, Hondaracing, NOS, whatever you can get your hands on.
Old 08-31-2006, 08:15 PM   #19
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Re: 2.5L Performance Upgrades

Quote: Originally Posted by 2.5FearFactory
well...since you seem like an intelligent guy who will be a productive member of the S community...I'll let you in on a secret...you will be the FIRST one to know this trick without first having gone through the initiation process and knowing the secret handshake...

stickers....seriously. lots of them. Type R, Hondaracing, NOS, whatever you can get your hands on.
Good one
Old 08-31-2006, 08:26 PM   #20
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Re: 2.5L Performance Upgrades

sweet....you have a sense of humour...welcome to the board

alright...let's start from the basics...in your initial post you said what's worth your time and money. HONESTLY....*NOTHING* on a TwoFive is worth your time and money....what sort of budget do you have to work with? how deep do you want to get into the engine?
Old 09-02-2006, 01:41 AM   #21
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Re: 2.5L Performance Upgrades

In all due honesty, I was just looking at quick things like this chips I have seen some guys talk about on here. Anyone actually try them and see if they work?
Also was wondering a good muffler to go with, I took my cat out and I need a muffler that will not sound ricey.

Also, flipped my lid (Waste of time, flipped it back, lol)
Old 09-02-2006, 02:11 AM   #22
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Re: 2.5L Performance Upgrades

From what i've heard, the chips aren't worth the money. And a good muffler that doesnt sound ricey would definatly be a magnaflow!!!! (HIGHLY recommended). My exhaust is 2.5 to the muffler, with dual 2.25 pipes out the rear. Sounds almost as hot as Tamas' mom when she's screaming Brian's name
Old 09-03-2006, 12:03 AM   #23
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Re: 2.5L Performance Upgrades

haha very funny!

With the air cleaner lid....cut away the sides! that REALLY opens it up free mods FTW!!!

chips...I'm not sure I haven't had mine chipped yet, and I don't think I'll bother. I've heard good gains about it, but I've yet to see a before/after dyno, so I'm a bit skeptical.

Mufflers: again...if the rest of your truck is not built, it will be more sound than anything. I've got a 2.25" system w/ a Magnaflow and a turndown and I LOVE it....

Clifford performance makes a header (if you want to do the full exhaust) that I've heard gives you good gains, BUT...the header alone is 3-400 and from what I've heard it's not a perfect fit, so you'd have to redo your whole exhaust.

A cam really wakes these engines up, but again, only with the help of a header, and then you're into well over a grand (header, cam, exhaust) for not too much power.

The way I built my motor is when it started rod knocking I tore it down and started sourcing parts...I found *ALL* of my performance parts cheaper than OEM replacements (just gotta look around ) and stuff like shaving the head 20 thou instead of just smoothing it was 5 bucks extra. The only thing I spend money on basically was my cam. And now that I've got all the core stuff done, I'm thinking of doing a few more (intake/header/redo exhaust/convert to carb).

But while my motor was running happily, I left it alone cept for the intake/exhaust/ignition and a V8 flex fan (again...got it when my OEM clutch fan died)

ooh that reminds me....a junkyard (V6 '90s Taurus) electric fan will free up a few ponies!

I mean if you gave me a ROUGH budget and how deep you wanted to go into it, I could help you better....but unless you want to spend several grand on it, it's really not worth messing with it.
Old 09-04-2006, 11:52 PM   #24
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Re: 2.5L Performance Upgrades

Well I figure by the time next summer rolls around I will be due for a rebuild. (At my mileage rate I will be over 200,000), and at that point I intend on putting my 350 in, but before that I wouldn't mind spending a couple hundred on this motor. Exhaust wise, I am already alright I Think, with no cat and all. I just went a bought a new injector today and it reduced my performance under acceleration, which sucks, but makes perfect sense. My past injector was more of a splatter gun than anything, so it poured a ton of gas into the combustion chamber under throttle, but also wasted some, and now it is working right and not doing that. But, on the bright side, I am getting about 7 more MPG.
Old 09-04-2006, 11:53 PM   #25
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Re: 2.5L Performance Upgrades

As for an exact budget, I am thinking $200-$300, maybe a little more depending on the gains. Don't want to go any deeper than taking the head off. Got to pay off my damned speeding ticket first. (Ha, cop thought I was SPEEDING in a 2.5L, what a joke )
Old 09-05-2006, 10:03 AM   #26
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Re: 2.5L Performance Upgrades

Ive been tinkering with my 2.5L lately... so far Ive did...

Cat delete
2.5" Flowmaster exhaust
16" taurus Electric fan
Flipped the lid for now (building a custom CAI)
Ported intake and exhaust runners a bit (planning on doing a full P&P here shortly)

So far with every mod I do to the engine it responds to it pretty nicely...

Will a 2.5 ever make alot of power... probably and wont have to take thousands of dollars.. just needs to be well engineered... the 2.5 is pretty much half of a 302 V8... with all the same parts damn near... so if you can make a 300 or 400 hp 302... then you can make a 150 - 200 hp 2.5 easily... but anything more than that and it wont be that reliable...
Old 09-05-2006, 11:17 AM   #27
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Re: 2.5L Performance Upgrades

Save your money for goodies for the 350 If you don't want to go deeper than the head off the only options would be:

decking the head
valve grind
ignition (cap/rotor/wires/plugs)
CAI (has to be custom-made, if you're interested I can tell you how to make one for like 20 bucks)
header (they're close to 400 US)
Taurus e-fan

If I were you, I'd maybe do the e-fan (you could most likely keep that for your V8 setup), and a CAI (so damn cheap). With the rest of the stuff you won't really notice a diff. especially on a motor w/ a stock bottom end and high mileage.

I'm not sure if you've said it, but what year is your 2.5?
Old 09-05-2006, 11:33 AM   #28
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Re: 2.5L Performance Upgrades

i wanna make a $20 cai for my 2.5


post a how to !
Old 09-05-2006, 12:14 PM   #29
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Re: 2.5L Performance Upgrades

haha okay...I'll do a how-to in a bit, but here's a quick run-down of it. (I'll do pics too).

What you need:

3" ABS tubing from any hardware store (say...3 feet of it, then cut to required length)
"top hat" (the part that goes directly from a TBI) from a late '80s Cavalier/Beretta 2.2
cone filter
hose clamps
some sort of a plug to block off holes on the top hat.
some sort of a shim (I used 2 Coke bottles cut apart for style points) because the OD (outer diameter) of the cone filter will be the same as the OD of the ABS tube.

get the top hat...it'll be a very hard piece of plastic (I don' tthink there's any metal in it, but it feels like it, so it might be haha), chuck everything else in the garbage. put the ABS tube into it, it will slide right in, tighten the hose clamp on the top hat (the one it came with). cut ABS tube to lenght.

block off all unnecessary holes on the top hat.

wrap your shim (thin gauge aluminum works PERFECTLY) around the back of the cone filter and the end of the ABS tube, put 1 clamp on either end of it, and voila! you're done.

If it makes no sense it's 'cuz I'm in a hurry to get to school hahaha....my apologies for that, let me know if you need more clarification.
Old 09-05-2006, 12:16 PM   #30
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Re: 2.5L Performance Upgrades

few pics of it on the truck:









Old 09-05-2006, 12:17 PM   #31
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Re: 2.5L Performance Upgrades

my bad...don't chuck everything after the "top hat"...make sure you keep it all until the end of that "accordion" piece....sorry for the shit quality pics, they were taken a long time ago w/ my camera phone...I'd take better pics, but I'm several hundred miles away from my truck haha
Old 09-05-2006, 12:38 PM   #32
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Re: 2.5L Performance Upgrades

sweet so all i need is the "bonnet" from a 80's berreta 2.2? and some tubing and ish?
Old 09-05-2006, 04:31 PM   #33
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Re: 2.5L Performance Upgrades

pretty much, yeah I got the "top hat" for 5 bucks from a wrecker and I paid like 8 for the ABS tubing from Home Hardware or Home Depot, can't remember
Old 09-05-2006, 10:57 PM   #34
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Re: 2.5L Performance Upgrades

What difference is that from the normal intake system? Seriously? If it really makes a difference, I am interested in doing it, but if not, I don't want to waste my time.

Either way, what am I looking at if I want to slap a new cam in there, suggestions, and experience? I mean, hell, my motor only has 166k right now, I just do a ton of driving.
Old 09-10-2006, 05:14 PM   #35
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Re: 2.5L Performance Upgrades

from what I've heard, a cam won't do much of a difference unless you do AT LEAST the header/exhaust as well (header alone is almost 400 bucks from the one and only place that makes'em... Clifford Performance).

I got mine reground for about 200 bucks Canadian...just find a reputable shop and they should have a couple of grind profiles on-hand. (the shop that did mine had a street and a strip grind, plus any custom grind I wanted). Since they're roller lifters, you can reuse your lifters, but thanks to where the cam is it's a bit of a bitch to re&re it if your engine is in the truck (you have to take out at least the grille and the rad, but I've heard the whole rad support might have to come out as well). I did mine w/ the motor out and apart, so I'm not 100% on that.

you may consider hitting up http://www.tbichips.com and get a chip burned w/ your specs once you've got your cam
Old 09-10-2006, 05:14 PM   #36
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Re: 2.5L Performance Upgrades

oh yeah...the CAI isn't worth it...I did it for the fun of it lol
Old 09-11-2006, 12:22 PM   #37
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Re: 2.5L Performance Upgrades

if your 2.5 is not an a codde, find one of those heads, they are prolly the best part you can get for an older 2.5. bigger intake ports,better exhaust ports, thinner valve stems (flow better) and better (stiffer) valve springs. Just watch for cracks between intake and exhaust valve seats. get a machine shop to crack check any head and if its good deck it a tiny bit to get rid of warpage and gain slight compression. you can't go very much because the head surface is thin.
To improve the stock manifold, get a header flange, cut off the old spring flange and weld the new flange on - the factory flange is what looks like a major restiction to flow. (1.25 -1.5 id)
For headers, find a sbc drivers side header, and do a little mods - cut off the sbc flanges, re-angle the outside to tubes inward and weld 2.5 manifold flanges on it. (use a gasket ot get the tubes at the right angle, bolot em up and then give them a good tack weld.)
I have done the manifold mod, i race with a guy who has the header mod done, and i have the a code head done to my truck. the motor pulls up to 5200 with an 84 non roller stock cam and revs up to 5800 under load 2nd gear on the track. I plan on getting an isky cam and seeing how the motor responds. she will rev to 6000 free revving and the track is too short for me to see if she will go that high under load.
Old 09-11-2006, 10:13 PM   #38
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Re: 2.5L Performance Upgrades

I've got the A code motor...about TBI Chips, anyone use them and know if they are worth it?
Old 09-12-2006, 01:34 AM   #39
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Re: 2.5L Performance Upgrades

Rizzle: welcome to the board...sounds like you know what you're talking about...good to hear original ideas like you have

fatman: I've HEARD that they're pretty good...and they're fairly cheap...like 100 or under...but...they're the LAST thing you should do to your motor...when you decide that you've gone as far as you want to go, do the TBI to match all your mods.
Old 09-16-2006, 12:02 AM   #40
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Re: 2.5L Performance Upgrades

if you want extra hp out of your truck...first off...get a grinder with a cutting wheel..go under ur truck and cut off your exhaust right before the cat...you won't be able to get an inspection sticker, but backpressure makes a big diff. on an iron duke.
then...keep that cutting wheel on there...take ur grille off and cut a square into your firewall right in front of where your intake hose mounts up to the firewall...DON'T flip your breather over with this because it'll defeat the purpose of your make-shift ramair...also, look in your intake duct and everything and make sure it doesn't have any baffles in it...take any restrictions out...
then...get you a temp switch kit and an electric fan...it'll help a little
...so far this costs around 80 dollars...
then...if you're still not happy...go to tbichips.com and get you a chip...
still...you may not be happy...
invest in a LuK clutch
.30 pistons
Comp Cam
Hooker Header
...
and if all else fails...put a 50 shot of nitrous...lol

people are probably gonna read this and laugh at my ram air idea...it works well though, better than anybody else's intake i see on here...and they make a hiflow airaid replacement filter for your breather...if that doesn't suffice...you can leave your stock filter out and put a cone filter inline with your intake tubing...
and this is pretty much all you can do that i know of with a 2.5...i understand that you don't want a 350, i don't blame you...it's more fun to beat a 350 with a 151...lol...they just have some 4 banger haters in here...my saturn can smoke your silly 350's!!!! peace
Old 09-16-2006, 01:14 PM   #41
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Re: 2.5L Performance Upgrades

you have some good points, but I think some of that stuff needs to be refined.

cutting the cat out is a good idea...however, cutting the whole exhaust in front of the cat off is waaaaaaaaayy too nuts. I dragged my exhaust off once right where you said to cut it and drove it like that for about 800kms and it was pure insanity. My ears were ringing for three days. It was just ludicrously loud.

are you sure you don't mean cut the rad support? I can't exactly picture your ram-air...got any pics of it?

e-fan is definitely a good idea and so is the LuK clutch...I've had my LuK in there for a while and when we took it out (when we were rebuilding the motor) it had about 50K kms on it and still looked like it had most of its life ahead of it.

oh...and I doubt a budget 151 will ever beat a 350. You'll have to dump thousands into an Iron Duke (if you can find the parts anymore...ie: SD stuff) to even keep up with a stock V8 S10.
Old 09-16-2006, 02:52 PM   #42
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Re: 2.5L Performance Upgrades

rhodi: If you would have read my posts, you would know I took the cat out a long, long time ago. On top of that, I have seen in numerous places that the Duke's actually like a little bit of back pressure.

I'd much rather have the 350 than this damn 151, but right now I can't spare the extra $2k or so for a swap.

Elaborate more on the Ram air idea, I cannot seem to visualize how you did it.

Last edited by fatmanmitch; 09-16-2006 at 02:53 PM.
Old 09-16-2006, 03:21 PM   #43
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Re: 2.5L Performance Upgrades

Quote: Originally Posted by 2.5FearFactory
you have some good points, but I think some of that stuff needs to be refined.

cutting the cat out is a good idea...however, cutting the whole exhaust in front of the cat off is waaaaaaaaayy too nuts. I dragged my exhaust off once right where you said to cut it and drove it like that for about 800kms and it was pure insanity. My ears were ringing for three days. It was just ludicrously loud.

are you sure you don't mean cut the rad support? I can't exactly picture your ram-air...got any pics of it?

e-fan is definitely a good idea and so is the LuK clutch...I've had my LuK in there for a while and when we took it out (when we were rebuilding the motor) it had about 50K kms on it and still looked like it had most of its life ahead of it.

oh...and I doubt a budget 151 will ever beat a 350. You'll have to dump thousands into an Iron Duke (if you can find the parts anymore...ie: SD stuff) to even keep up with a stock V8 S10.

yea i think he means the rad support
Old 09-16-2006, 05:49 PM   #44
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Re: 2.5L Performance Upgrades

lol, i'm sorry guys..i DID mean the radiator support...not the firewall, i was half asleep last night looking over the forums...i did pull my cat off, i cut my pipes off right before the cat and i'm running my pipe back to the rear of the truck and putting a hiflow muffler on it...i soooo hate the breather set up on our trucks...it doesn't give you much room to be creative with an intake system...anyways...i gotta go i'll talk to ya'll lata.
Old 09-17-2006, 04:52 AM   #45
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Re: 2.5L Performance Upgrades

Quote: Originally Posted by rhodimusracing
lol, i'm sorry guys..i DID mean the radiator support...not the firewall, i was half asleep last night looking over the forums...i did pull my cat off, i cut my pipes off right before the cat and i'm running my pipe back to the rear of the truck and putting a hiflow muffler on it...i soooo hate the breather set up on our trucks...it doesn't give you much room to be creative with an intake system...anyways...i gotta go i'll talk to ya'll lata.
lol so you did NOT cut off the exhaust after the cat, you simply installed what's called a "test pipe" or "straight pipe". Most of us who don't have to mess w/ emissions do that right away

I dunno, I just junked my whole breather setup....hahaha...seems to work fine still
Old 09-18-2006, 12:08 AM   #46
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Re: 2.5L Performance Upgrades

On the subject of the exhaust system, the 80, 81 chevy citation had a dual outlet cast iron exhasut manifold(I bought mine from a junk yard for $35) which I think might work in a S-10. However; aftwards you would have someont build a complete custom exhaust. sounds like a lot of work, but it did help the power in my circle track car.
Old 01-21-2007, 11:59 PM   #47
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Re: 2.5L Performance Upgrades

you wanna know how to make power - i got you 2 real ways - the cheap side and the smarter side
1) cheap side - find a set of racing circle track pistons (used is cheaper) rings to match, and deck you block around .090 thou - find a code head and raise roof, and you end up with 11:1 comp and a really good quench. runa comp cams 52- 123-4 to bleed a little cylinder pressure out and you have loads of power. a reve box is reccommended unless you like having a crank in 2 peices like we ended up doing - 8000 rpm is NOT crank friendly) id show a vid but the flywheel isn't connected to any rods anymore. this was our build untill today. it had about 1 hour of run time on it not inclding warmup
2) 327 pistons either valve releifs or not (w/ - 11:1 w/o 11.7:1 compression) w/ the 1.671 piston pin hieght, 6 inch sbc aftermarket rods (2.00 rod journal) w/ only roughly .020 shaced off block (big fan of quench distance) stock rods will not work - stock rods are .050 longer and your piston will hit your or be very very close.
port work again, airflow mods neccesary - either a 2barrel rochester or holley or a v-6 2 barrel thottle body. Cam either same as above or get your hyd. roller regound for 212 duration or more. lift is not as important .450 is ok. safer smarter build but slightly harder on wallet FIRST time around. doing ths way may stop a rod bolt from letting a rod see daylight.

for both builds try using comp cams 986 (i'm preety sure) valve springs, the stocks are bound at a hair over .500 lift, not safe clearance for .490 lift or up. (u want about .040 thou or more safety)
Again a rev box is highly recommended. MY driver seems to not listen to my telling him is should last arounf 6500, so he cranks her to 8000 b/c the clutch wasn't bled full (slave leaking, kept loosing full cltuch) so a rev box WILL be installed wether he likes it or not. i prefer having my flywheel attached to my crank to my rods thank you. my rev limit will be around 6500 or so. where you put it is up to you. i think w/ lite pistons (420grams or lighter) 7000 is ok if you like taking educated risks.
I've really looked into these motors if you wanna know small tricks just send me an e-mail, i'm pretty sure i can help you. i really know these motors - when shaving a block .090 grinding of the bottom of the #4 ehaust flange is neccesary for intall.

None of these mods are for engine health, they will require rebuilds more often and cranks and the like either replaced once in a while b/f they let go or crack checked.

Last edited by Rizzle; 01-22-2007 at 12:04 AM.
Old 01-28-2007, 08:25 PM   #48
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Re: 2.5L Performance Upgrades

a 90 s-10 with a 2.5 was given to me for free. well it has some problems, but it will burnout all thru first and about five feet in second. it's fast but i think its still stock except it runs rich..REAL rich. i'm gonna swap the motor over to another s-10 i have with a 2.5 that threw a rod bearing. so we'll see if its the computer or what that gives it so much power.
Old 01-28-2007, 08:42 PM   #49
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Re: 2.5L Performance Upgrades

a 2.8l with 7-8 psi will set you at the 200Hp mark
Old 01-29-2007, 10:26 AM   #50
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Re: 2.5L Performance Upgrades

Just took my cat off over the weekend, and added a higher flowing muffler. Couldn't tell a damn bit of difference. My crossover pipe seems to be really crimped though, so I would imagine that'd be my exhaust week point.

I don't think there is much that can be done to ad performance to these engines without opening them up. Just keep them tuned up(plugs, wires, etc.) is probably your best bet.

They're just slow!
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