2.5 on GLHS Stage II

[Mopar_Nutz]

Just dropped a 2.5 into my 87 SC to get it running. While I'm trying to figure out if I can get a 2.5 cal in a LM for it I need to be able to turn the key and drive it for Mopars at the Ranch car show. So the question is, where's a good place to start with running a 2.5 on a Stage II LM?

The car is just a stock 2.5 with stock head for now. TII turbo, ported exhaust manifold, 3" electric cutout. 2 piece intake, large NPR IC, +20's and a 255 fuel pump.

I know the Stage II runs a 2.2 a bit hot so I don't want to follow the usual simple advice of bump back the timing and throw +20's in. Should I mess with fuel pressure or cam timing as well?

Thanks, Ian

[slasky]

The only way I know how to do it right is to get a cal from TU. Paul is the only one I know of that makes an 87 logic module for a 2.5. The timing and fuel curves are different between a 2.2 and a 2.5. So backing off the timing and throwing more fuel in stops it from blowing up but does not cause it to run properly.

[tryingbe]

http://www.thedodgegarage.com/turbo_big_injectors.html


'2.5 engine with 2.2 computer and 42 pph injectors.

Ahh the one special case! Mopar Performance sells a 42 pph injector- It flows exactly 20% more then a stock 33 pph injector used in the 2.5 engine. Now from what I understand the 2.5 is 11% larger in displacement then a 2.2 BUT it's fuel curve is 17% larger... so what does all this mean? If you install a Turbo II 2.2 computer on a 2.5 engine the calibration will be 17% lean... unless you install a the 20% larger 42 pph injectors at the same time! This is the setup I ran on my K-car and it works pretty well and the extra 3% of fuel will get you up to 16-17 psi. Some cars seem to need a little tweaking with the fuel pressure and others have no problem at all. This of course lets you swap a 2.5 into a car like a GLHS that never had a 2.5 computer available for the application from the factory... you get the idea.. '

[Mopar_Nutz]

yeah I know it's not the best way to go, but I need the car up and running. I dont' have the time to wait on a custom cal.
I know the +20's are the best first step and I do have them in, but I'm concerned about the Stage II running a fair bit leaner than a regular TII does. If it's risky to run a 2.5 on a 2.2 LM, it'll be twice as dicey on a Stage II. Or so I'm assuming. Just curious if anyone has done it before I throw it all together and start to run it. I don't need huge power now, just enough to have a little fun with until I can get it done right.

Considering attempting a SMEC swap to open up more options....

[86Shelby]

The engine will run just fine with the stage 2 calibration if you have the electrical wiring converted to GLHS specs. Dial the base timing back to 4-8* instead of the stock 12*. You have the +20s so your fuel will be alright for the boost levels the calibration runs. I would recommend using the stock boost control if it's intercooled; then the LM can dial back timing AND boost if you run into detonation. If you do not have an intercooler I would just run a vacuum line straight to the wastegate can. It's not as much fun but it will get you by good and VERY safe.

I've been running a 2.5 on a stage 2 cal for over 2 years now will few ill effects on 2 DD cars. Used this combo in my GLHS and now it's in my GLHT. I found on the dyno that I had to dial my base timing back(from 8*) to stay out of detonation around my peak Trq RPM. I was using a grainger so I could have 16 psi by 2500 rpm. Right now the car is non intercooled with a line going straight to the wastegate can; figure 5-7 psi. It's enough to have some fun on poor 87 octane fuel. I've never had a problem with it starting or idling in the dead of winter or after a heatsoak in the summer.

Don't worry about the lack of ignition advance giving you low end power or starting issues, because they aren't there. The cal's ignition advance is a bit on the wild side for a 2.5, that's why you dial back the timing.

[86Shelby]

Figured I'd make a second post so in the info doesn't get confused. Right now I'm running a stock longblock '89 2.5 with GLHS intake/exhaust/turbo in an '86 GLHT w/GLHS electrical conversion. +40 injectors at about 40-45 psi(I think, can't remember offhand) and the GLHS stage II cal. My GLHS ran excellent when I had +20s at the stock 55 psi for 8 months; I never did have a driveability issue with those parts. I was getting ready to go with a bigger intercooler and a 3 bar cal; that's the reason for the AFPR and +40s. They aren't needed if you don't plan to go over 14 psi.

That calibration is very adaptive, and that's why I love it!. It will allow the engine to run fine with the +40s at 55 psi but it idles very rich(not black smoke rich) and there aren't nearly as many O2 sensor occilations as I'd like to see. In the interest of gas mileage I turned the FPR down. You can have one heck of a mismatched combination and that LM will still get you down the road just fine. :)

[GLHSKEN]

^^^^^ YEP. sIMPLY START WITH A BASE TIMING OF 8^ AND WORK UP FROM THERE.

[Mopar_Nutz]

Awesome. Thanks guys. Back to the garage with me! hahaha

[Mopar_Nutz]

OK I know this is going a bit off topic but since my setup is already posted in here...
I have 2 choices on cams to go on this car. a stock 89 2.5 T1 roller, or an 88 TBI roller. How do you think the car would react with this setup to being 4* advanced with the 88 TBI roller cam and round tooth sprocket? Or should I just drop in the 89 T1 cam?

I know it could be a bit of a handfull down low with the 2.5 torque, short tires and 555 gears, but really don't know what to expect with the stage II cal and retarded ignition timing.

[Mopar_Nutz]

Alright the car is all together and running like CRAP. Completely lethargic and backfiring badly.

The backfiring is right off idle. As soon as I touch the gas pedal it starts backfiring and spluttering. It clears out as revs go up.
It won't give full boost at WOT either. It'll sit at like 6 psi or so until I ease off. When I get to about 1/2 throttle, boost pegs about 16. But the car doesn't really pick up.

I've messed with the cam timing a bit but no help. Any ideas?

[iTurbo]

What injectors and base pressure? Which cam and TBI or turbo cam sprocket? Any codes? Sounds like it could just be a vacuum line issue too.

I'm running a nearly identical setup in my Omni GLH Turbo, although I'm running the 2.5L TI SMEC on it.

[Mopar_Nutz]

OK problem solved! Pulled my plugs to check compression and found 2 very rich cyls. So I was suspecting leaking injectors but out the corner of my eye I noticed some arcing on the coil wire (dark out now). So I swapped in my Aurora wires and it ran like a dream! Aside from my AIS crapping out then and there.

Wow a 2.5 with a few bolt on's rips in a light car. 2nd gear spinning on 9 psi!!!! Can't wait to boost it up hehehe

Oh yeah, +20 injectors. 55 psi pressure. 88 TBI cam with 89 TI cam sprocket. Thanks for the fast reply. I thought like you did at first, until I stumbled across the problem at random.

[86Shelby]

Nice to hear it's running well for ya now. Just wait until you feel 14 psi. It's always nice to hear the tires clawing at the pavement for traction in 3rd gear!!!

[Mopar_Nutz]

haha yeah I honestly think it would almost give the old Shelby Z a run for it's money on 23 psi. Granted that 23 psi was thru a stock IC so prolly not much better than 18 or so. hahaha