Doing the 3.4 swap into an 89 Trooper and wondered if anyone had any info on the advantages of this swap. Info or links to info would be greatly appreciated as well...


Anyone wanna buy a New (not rebuilt) GM 3.4 LQ1 crate motor <img src="/forums/images/graemlins/kewl.gif" alt="" />

When I did the first 2.8 to 3.4 conversion in 1999, there were some web mechanics that insisted that the 3.4 wouldn't work with the 2.8 ECU. I don't know of anyone who has found it necessary to make the change. Whether or not it would improve performance will have to wait until someone feels compelled to try it both ways and then dyno both options. (I am not talking about a butt dyno, but a real live, it costs some real money test).

Howdy Jim,

Not only am I swapping the 2.8 to the 3.4 but I am thinking about using the SFI system on the 3.4 and replace the 2.8 throttle body system... I'm thinking that the ECU for the 3.4 (have both engine and ECU out of the 95 Camaro) would just need to be wired into the existing 2.8 harness circuits with custom jumpers, then run the specific sensor circuits separately.
IÆve been going blind researching this in service manuals and schematics so I guess my major question is: Is it really worth it? If so, I canÆt seem to find any info on swapping the firing systemà The 3.4 is electronically fired, but the 2.8 has a distributorà ThatÆs where I kinda vapor lock and get totally lostà

So any info, thoughts and comments would be greatly appreciatedà

A guy over at PlanetIsuzoo has done a 3.4 SFI swap, it's running and he's been fiddling at it for quite some time now. You'll also find postings about this in the Swaps sections at the "60 Degree V6" site: http://60degreev6.com/forum/

Personally, I think a hot-rodded TBI setup has it all over a stock SFI installation in terms of simplicity and also performance. The SFI might give you a broader torque curve and maybe more 'refined' operation, but the TBI is a lot easier to deal with and performance gains come relatively cheap. A stock 3.4 SFI setup only gives 160 HP, and guys running slightly-modified 3.4 TBI-d motors have seen as much as 187 RWHP on a dyno.

Now, if you were going to go to all the effort of rewiring the Troop for an 'upgraded' EFI system, I'd build a 3.4 with aluminum FWD '3400' heads which breathe way better than the cast-iron RWD heads. You'd have issues of adapting the FWD manifolding and hardware/accessories into a RWD application. You'd need to use different pistons, as the FWD 3400 pistons are dished to account for the FWD alum heads' much smaller 'squish' area. Using RWD pistons with alum heads would give you an extremely high compression ratio.

Get hold of "RedOktober" at the Planet Isuzoo forums if you're interested in this mod. He can fill you in on his progress so far.

http://forum.planetisuzoo.com/profile.php?mode=viewprofile&u=6708

I have a bunch of info pertaining to the basic 2.8-to-3.4 TBI swap, if you'd like the files just send me a Private Message with your e-mail address and I'll forward the info to you.

HTH......ed

Hi Ed... and thanks for the info... after today I will probably go with the TBI system, seems the ECM I bought isn't as complete as I was lead to believe, the wiring into jumper boxes isn't a big deal but at this point I need to get on with it.

Was also told that 99 Grand Prix aluminum heads will work on it also, gonne check into a set...

Thanks again...

Rick

Don't forget that if you use FWD alum heads you'll have to change out the pistons to FWD'rs.

And the TBI manifold won't bolt up. If only someone made an adapter for TBI intake-to-alum heads!

Ed,

Gotta break while the machine shop replaces the cam bearings so wanna run some of the mod numbers past you guys and get some thoughts...

Gonna look kinda funky ... not holding the formats...

Mods in the works...

TBI:
Port Match and polish the intake.
RV Morse Machine 62-4.3V TBI
Flow Matched TBI Injectors
GM TBI Adjustable Regulator & pressure gage.


Cam: A.R.I Probuilder phase 2 Hydraulic lifter cam.

Duration Lift
Adv @0.050 Lobe W/1.5 LSA IC
IN EX IN EX IN EX IN EX
264 274 204 214 .2820 .2820 .423 .423 109 105

Heads: (gonna stick with the iron)
Port Match to Intake.

Valve Train: Z28
Springs: OD: 1.265" ID: .780" 110 Lbs @ 1.710"
305 Lbs @ .500" Lift Coil Bind: 1.150"
Absolute Maximum lift- .500"
Moly Steel Retainers - 11/32
Hardened 7 degree locks - 11/32
Rockers: Steel 1.6 Ratio 3/8 stud


Cooling:
16' 2799 CFM Electric Fan (15.75/16.25/3.75)
Moroso Proform Electric Water Pump Drive Kit.

ECU: Dumped the stock chip and a chip from D&S Speed Tuners to custom burn a eprom to use, have my trusty CF-28 with various sets to check them out once I get numbers from the running engine and fine tune the 4.3 TBI.

Havn't run this through any dyno software... been to busy juggling... that and stacking suspension parts... ton a those in the works also...

Wanna see what this Moab thing is all about...

Thoughts?

That's gonna be a real nice setup, lotsa Sweet stuff going on!

Gonna be interesting to see how much having the chip custom-tuned adds to performance and driveability.

Are you getting roller-tipped 1.6 rockers? The reduced friction from roller tips will add a bit more Juice, besides lowering oil temps and reducing valve/guide wear.

Last thought, what kinda exhaust mods are you planning? That motor's definitely going to need more breathing.

Have Fun..........ed

Ed,

Hey thanks, hopefully it will get there soon... Thank you and all the gang that contributed to the great write ups on this swap... Great reading and awsome into in there...

Yeah, using steel rockers, was going with a set of alum but with this set of steel I get the strength I wanted. Thought I would be farther along but taking my time and makin sure...

I have several ECM data dumps I've been going over, 2.8s not all that great but will give me the data I need to figure out what its doing. Don't tell GM but I'm working on decompiling their control program to get some idea of function. Manually took some cam angle measurements, lobe lift etc and wanna see how they actually transfer. Soon as I get something I'll throw it in here plus once its actually tested will burn a few and send em to ya.

Dyno sim says 182HP 191TQ @5000 RPM at the flywheel with stock exhaust... not able to input z28 spring info or under drive pullys, electric water pump data, TBI info (Using 300cfm and got a email in to Vic at RV Morris for some actual CFM data. P&P info should be interesting as well... Once I get it done wanna take the sim dyno info and see how close it is to actual.

Headers are a different story... Talked to Summit about a Cat-Bac system for the engine... But that will take some mods too... Thinking about just taking a set of Pacesetter and custom making a set of duals... Dont like the 1.5 or 1.62 primarys... Want at least 2 inch, so will probably do the cut and paste thing... Gotta stock up on super glue and grinding wheels/stones... Hedman makes a close set too but thier 1.5/2.5 also...

I'll keep ya up to date...

Update: Talking with Vic at RVM gives me a 595 CFM base for the intake plus some for the flow matched injectors, CFM Tech makes one rated at 620 but naturally more $$$... Also looking at maybe picking up a 1' spacer and seeing how far beyond the 44.45mm base the 4.3 and 2.8 intake can be pushed...
Update: Part DOH... Well round 2 with the cam bearings, seems these guys didn't have much xp with these so they missed the oil holes... Got just about everything ready and the Dyno Sim says the motors at 244hp and 233tq ATF but we'll wait and see what the real one says I think... Got the data from various 3.4's plus the default data from the Camaro's ECM, plus lots a stuff from the 2.8 so I'm in the process of sorting it out. Naturally neither the stock GM EPROM's nor purchased speed chips can be easily re-written but I have replacement chips I can write test data to. Once I get a working one done I will run the numbers by ya. Also have a Edlebrock Performer in the works also plus both the spacers so we'll see...