2.8L needs some direction

[Trooper_on_36's]

I've read alot of posts on here and there seems to be a hundred different directions i can go with the 660 setup, to start here's what I've got:
89 Isuzu Trooper II, 2.8L Iron head(With only 10K miles on a Jasper engine), 5spd, Solid axle swap using a toyota front end, roughly 7in of lift, factory 4.56 gears, and 36in tires. Through 1st and 2nd it has decent power and it ok in 3rd, but falls off bad in 4th and 5th, I should probably regear it but I like the fact that I'm only doin 2500rpms in 5th at 70mph. I'll probably end up going down a gear size to 4.88, but that means swapping out for a toyota rear, and I want to see if i can get enough out of the 2.8 to see if I can work with it. Heres a couple of different ways I could do it, and please jump in and tell me if I'm wrong:

1. Get 3.1L internals and swap into my block, and while its apart bump up the compression either with milled 2.8 pistons, or milled heads etc.. along with the normal power adders, 4.3L TB, Cam, 1.6 rockers, headers, etc...

2. Do a 2.8L FWD head "hybrid swap" and wire it for MPFI using the stock TBI ecu wired to the six injectors, like the thread a few down talked about, and either leave it like that, or what I'm really wanting to do, put a M62 supercharger, which is no problem fabing up a UIM for it.

3. Leave the TBI set up and supercharge it, I'm not looking at doing more than the factory set 7psi, but I'm just not sure that the TBI set up would be able to handle it or keep up with the fuel demands

4. Or screw it all and swap in a 3.4L, but I really don't want to ditch my newer 2.8L until I've blown it up, but what I really like is that almost everything I do to the 2.8L(bolt on wise) will transfer over to a 3.4L when that time comes.

I'm a Certified Tech, and have been working on cars for over 10 years now, build rock crawlers and little Suzuki cars, but I'm used to building high reving, engines that don't see power til over 4-5grand, like my suzuki, but I need something with alot of lowend and power from and below 3k. I'm looking for some serious input on this so any help you guys can give me is much apreciated.

[Trooper_on_36's]

Nobody? Well my favorite option right now is to see, if the TBI system can take low amounts of boost, with the larger TB and Injector, and other few add-ons. I'm not going to be racing with it, probably very rarely at WOT, but something to add some grunt, some bottomend to this motor, and if I blow it I'll go to the 3.4L, or if the TBI system can't take the boost I'll go to MPFI weather its with a hybrid swap, or from a camaro setup, I just want some opinions on this since I'm new to the 60*V6's. I know the suzuki guys have gotten the TBI setups to work in the 3cyl with low ammounts of boost(5-7psi), with high volume pumps and different tricks to get it to run richer, I just don't know about these motors. Any help is greatly appreciated.

[neo71665]

The problem with boosting TBIs is to get them to seal. Used to be a page somewhere with a guy running a 2.8 supercharged (in an 87 blazer) that had some solution (besides 0-ringing the TB shaft) that involved drilling a hole and running some hose. I looked but can't find it easily.



Found it and it wasn't a 2.8 but the guy swapped a 3.4 and ran a powerdyne with a ton of mods.

http://home.windstream.net/mcfly/s-series.htm

[geoffinbc]

You don't want a blow through supercharger on a TBI system. It is better to use a roots style blower on it. Especially if off idle torque is what you're after. Fageol used to make blower for the iron heads if you can dig one up go for it. I have never been able to get my hands on one.

If you want torque then stroking your 2.8L would be the answer if you intend to keep the stock block. I have just finished building a 3.2L (.040 over 3.1L) with a comp 252 cam and 1.6:1 rockers with port matched heads and intake with a 4.3L TB on top. I expect it to make good torque once I get it back on the road. It should take me a couple more days of work.

Before I started all this I even considered offset grinding a 3500 crank for even more stroke. But a head on my engine cracked and I was rushed into doing a rebuild and had no time for souring a crank and shopping for special parts. I was hoping for another year on my 2.8L but after 300,000 + KMS it had enough.

For the trail I honestly believe TBI cannot be beat. Its simple, uses the least amount of sensors and it must be the most reliable EFI system to date. If you ever have a problem on the trail it is simple to diagnose. Spare parts are everywhere on every truck from 1986 to 1995. During those years only the TPS sensor changed. Plus you can do a full fuel system service for little over $100

[Trooper_on_36's]

Yeah I really do like the simplicity of the TBI set up, and as you said you rarely see problems with it. I do favor the idea of stroking it to a 3.1 and just doin odds and ends to pep it up, but i think if i stay N/A I think its inevitable that I'll have to regear, I pulled my front tires off the other day to do some work, and the tires weigh about 110lb each its a heavy wheel and tire combo to power around with stock gears. I know its going out side the 660 relm, but i know like alot of the fiero guys, the 3800 is an option, but what I would like if I didn't have to do a custom flywheel, is a Caddy 4.9L. I would be able to retain the TBI system by making it fit and just step up to the 4.3or5.0 injector, and custom motor mounts and exhaust doesn't scare me a bit I just don't want to have to pay out ass for a custom flywheel, feel free to tell me if thats a bad idea, but 4.56's is a perfect gear ratio for close to 300ft/lbs of torque and 36's. But I don't know maybe 300ft/lbs of torque may not be out of reach for a 2.8/3.1.
Betterthanyou, let me know how the 3.2L works out, if it puts down some good power I might go a similar route.
Thanks for all the input guys!

[1986]

from research ive done in the past, 4.56 gears are ideal for 31"-32" tires. now you have 36"s WOW. id love to see some pics of that. cheapest way to go is regear, if you do it your self. id tryed a few bolt ons on 2.8s with not much luck, by the time you make some real power, youve already spent to much, but they do last atleast 200k. on my recent s10 i went straight to the 3.4

[Trooper_on_36's]

Yeah I've come to that conclusion that regearing is probably my best bet. It won't be too expensive if I retain the stock rear and not swap for the toyota. The Isuzu rear has one gear option other than stock and that's 5.38's, but the only problem is that the closest gears for the Toy axle is 5.29's, but talking to a bunch of guys on the pirate board, they says thats close enough. If I swaped for the Toyota rear I would of easily had to spend a little of a grand. I'll probably still do the larger TB, and some headers, but just regear it. If I get my computer back out of the shop I'll post some pictures of it up. Thanks for all the input guys.