[Warren87_28_4x4]

Does anyone know what the differences internally are between the two types of engines?

I hear the f-body engine coems factory with 9.5:1 compression and the HT crate motor is 9:1. Are they still rated the same?

The cam in the 3.4 is similar to the crane 2030...Exactly how similar is it? would it still be worth to put the 2030 in it?

Does anyone know if it is possible to put 3rd generation 3.4L heads on it while using my existing TBI setup and that is on my 2.8 right now? (Il need a special manifold to use with the heads)

thanks for any info

 

[Vegeta]

I wanna know why the crate motor has 1.6" intake valve, and 1.42" exhaust. It should be 1.72" for intake. The camaro should have the larger intake valve for sure. As for the cam, it looks like the same cam. GM uses crane cams for their performance motors, so I wouldn't be surprised.

Do you know what the difference in the gen 3 heads is? I know the FWD blocks pretty well, so if it follows the same guidelines, then I would say no, they won't match up very well. In fact, I would think the 3.4 would be port fuel injected right? Im not sure what the point of using your TBI setup would be unless you don't want to change the computer to use the 3.4 (which is a bad idea as well)

 

[wis bang]

2.8's computer CAN handle a 3.4!

My '88 has the crate motor from GM and I'm using all my stock 2.8 components and the computer is doing very well. No trouble codes in over 5,000 miles. It surges when it's first started, until it goes into closed loop, then it's fine. Once you've got on the gas, it's ok and you only notice the surge if you try to run slo in 1st or 2nd. The camaro used the same heads as the 2.8 used from '86 when they went to TBI it's got 1.72' intake valves & 1.42 exhaust. Pulls like a mule & I'm getting better gas mileage!

 

[Vegeta]

The computer needs to know the displacement of each cylinder to make the best calculations. It might work, but its not optimal. I bet your BLMs are way low.

What is the injector size difference between the 2.8 and 3.4? Are you using TBI still?

 

[wis bang]

still stock TBI

Once the computer starts reading the o2 sensor [closed loop] the TBI has alot of power. My truck is a 5-speed and it has great power in each gear. I get a pain in my leg from NOT stepping on it! Everyone in front of me is now going TOO slow.
It only surges for a min or so and I don't see it when I can just get on it and go. At work I have to cruise thru the lot b/4 I can step on it and some times I have to push in the clutch 'cause its buckin...It's gone b/4 it's too anoyin'

 

[Vegeta]

Ok, then you most likely just need to reprogram the chip so it knows about the extra displacement. It already know the injector size, but it really needs to know about .6 liters of total displacement. GM doesn't offer a chip or anything to use?

 

[wis bang]

GM can't support this swap

The HT 3.4 crate motor is only emissions approved for 82 to 85 w/ a carb. I voided the waranty by using it in an '88 w/ EFI. They cannot legally offer any help. I was buggin GM Goodwrench.com about the 3.4 and they said they can't help me BUT I should check out several sites to see what other s-10 owners were doing with their trucks. They gave me sites like this one as well as JTR.com.
I feel that an increase in fuel pressure might help, except that I like getting over 20mpg as this truck is my daily driver and I have no interest in taking it to the track. I went w/ the 3.4 as I figured I'd be keepin' the truck for a few more years and I wanted to enjoy driving it. Except for those first few min, it runs better than the 2.8 ever did AND it gets better gas mileage 'cause my foot is not in the TBI like it was when I had the 2.8 (the scrap metal dumpster @ work is now empty so the old 2.8 is on it's way to being re-bar or whatever they make from scrap metal).
I've seen a vacuum operated fuel pressure reg. mentioned on the F-body board but it does the opposite, decreasing vacuum ( from WOT ) increases the fuel pressure. It allows the guys w/ wild cams a chance of idling by setting the pressure lower @ idle. Maybe converting my O2 sensor to a 3-wire type so it warms up quicker would alow the computer to switch to closed loop a little faster.

 

[Vegeta]

Raising your fuel pressure will do more harm than good. The computer has to know the exact amount of fuel it is delvering in order to compensate the pulse width based on the O2 feedback. If you raise the pressure, you will have more flow, and the computer will think that its adding a little, or taking away a little, when it is actually working with a lot.

Do you know anyone who has worked with the code in the older S-10s? I don't know anyone, but I could possibly change the displacement in your chip if I had the code to look at first. Its likely the only way to get it running right the entire time.

 

[wis bang]

I'm happy with it the way it is. I know that a few 3.4 swaps have passed NJ emissions w/ the stock TBI and stock chip. That was my main worry. Fuel pressure does matter, GM's spec for it's TBI's is 9 to 13 lbs. I'm sure those that reach 12 to 13 lbs run better than those that just made it @ 9lbs. I would like to know what my pressure is at, and someday I might get a gauge & check. Most important is the fact that it drives better than the 2.8 and the emissions tester won't be able to tell that it's a 3.4! My reg is up in March so I'll find out then if I have any problems but for now I'm just happy w/ no trouble codes from the computer. The way it runs, I'm positive that the computer's ability to self adjust is working.

 

[Vegeta]

The injector has to be rated at a certain pressure. Try to get it at that pressure and it should be better. That much of a variance though is odd. I thought you were going to raise it beyond spec though. If you are just going to the high end of spec, the computer should be set for that anyway. It may not be a noticable difference, but to the computer it is. You can increase your milage with a tuned chip. The change to letting it know its a 3.4 maybe help, im not sure. If its good enough for you now, then don't bother. I just want to let you and anyone else reading know what the computer is seeing.

 

[GNNOVA]

Vegeta I'm getting reading to swap to a Camaro 3.4 this spring. I like what you were talking about burning a chip. I have a chip burner that I can use. Did you ever get the codes for the S-10. Also you wouldn't happen to know the specs on the 95 3.4 cam.

Ken
93 S-10 2.8 5speed

 

[betterthanyou]

You do not need to burn a chip. The computer in the TBI trucks is not that advanced and does not need to know the displacement. On a port injected car it matters but not on TBI. If you dropped in a 350 TBI the computer would run it fine. The computer has preset fuel tables that are based on MAP, O2, and TPS readings and based on these is knows what load is on the engine the ratio of the fuel mixture and the position of the throttle. It then delivers fuel accordingly

The reason Wis Bang's truck surges when not in closed loop, is because he still has the 2.8L injectors and he is not getting enough fuel to the engine and it is actually stalling out a little. When the computer is in close loop it is delivering a preset amount of pulse width to the engine and is not modifying its program based on the lean condition because the O2 sensor is not hot enough. To overcome this problem you should install the 4.3L injectors. These will run rich in open loop but it is better than running lean. To go even a step further like I did, install an external fuel pressure regulator (http://members.shaw.ca/betterthanyou/regulator.htm)and tune it until the computer no longer has to modify the pulse width from the norm, and you will have a perfectally running truck in cloed and open loop. You will need a scan tool to do this.

Back to the original question. If you want to use the gen 3 heads you could. If you made a custom manifold and went to the FWD dished pistons. But of course no TBI manifolds exits for aluminum heads. The compression ratio should be the same the Camaro and the crate have the same bore stroke and pistons. The cam in the crate is the same as the Crane Cams PowerMax H-260-2 and not the 2030. I would keep the crate cam it is a good cam and will pull all the way to 5000. The crate has 1.72 intake and 1.42 exhaust valves. I dont know where the hell anyone got 1.6 intake from, those head were gone after 85 and are not even sold anymore.