Low Power with Large Turbo

[mr b]

Hello I was hoping to get some consensus on an issue I am having. So far 3 different opinions!

Unfortunately the thing is a dog. AFR is perfect and 17 psi consistent boost.
This motor put out 300 hp at the wheels when I had a 5-speed transmission in it on a 2.2 block. I had it rebuilt with a 2.5 block and swapped out to a fully built trans from Cindy. Now it feels like it has half the HP and torque.

I have an 8V TII motor in a Spirit
FWD MOTION Stage 3 Turbo 50 trim with a .63 housing.
Menegon Head
Ported 2 piece upper and lower intakes
TU Hybrid Header
Spearco FMIC
3" Exhaust
Boost Button Cal
and an A413 Trans with a Quaife LSD and 2800 rpm stall convertor.

DID I MENTION IT IS A SLOW DOG!!!

Some trusted friends say the turbo is too big for an automatic trans, others say the stall is too low and should be at least 3600 stall, and some say the FMIC is too big.
Others say play with cam timing even though its set to factory.

I am looking for input before spending $600 - $700 on a new convertor or $900 on a smaller turbo.

[cordes]

When does the turbo spool? I would think that the stage III wheel wouldn't be too pleasant with the auto, but it should still pull really hard up top with the build you've put together. Perhaps it's just a really narrow power band and high(er) higher up there when it hits with the turbo, 2.5, and auto put together? If the turbo isn't coming on strong until 4500rpm and you're shifting at 6k that would be a dog I bet. Especially when you hit the next gear and have to get back up there again before making power.

[tryingbe]

Is this your first experience with a 2.5L turbo engine?

I bet you are making 250 lb ft and 190hp right now.

Go back to 2.2L and the issue will disappear.

[mr b]

When does the turbo spool? I would think that the stage III wheel wouldn't be too pleasant with the auto, but it should still pull really hard up top with the build you've put together. Perhaps it's just a really narrow power band and high(er) higher up there when it hits with the turbo, 2.5, and auto put together? If the turbo isn't coming on strong until 4500rpm and you're shifting at 6k that would be a dog I bet. Especially when you hit the next gear and have to get back up there again before making power.

That's exactly it, narrow power band and then totally lost after gear shift. Do you agree about a higher stall convertor?

[zin]

I'll second the converter, And raise a possible cam choice, the two kind of go together ... of course you could just add some nitrous and call it good! Nitrous fixes everything ya know!

Mike

[mr b]

I'll second the converter, Andrew raise a possible cam choice, the two kind of go together ... of course you could just add some nitrous and call it good! Nitrous fixes everything ya know!

Mike

- - - Updated - - -

I'll second the converter, Andrew raise a possible cam choice, the two kind of go together ... of course you could just add some nitrous and call it good! Nitrous fixes everything ya know!

Mike

LOL it's all setup for NOS actually, window switch, remote valve, everything, but I wanted to get it right without the bottle first. What cam would you suggest and stall speed for the convertor?

[mr b]

Is this your first experience with a 2.5L turbo engine?

I bet you are making 250 lb ft and 190hp right now.

Go back to 2.2L and the issue will disappear.

Thought about it but someone sold my 2.2 block and it's a hassle to go back and change it out. Especially with forged pistons and such.

[tryingbe]

Thought about it but someone sold my 2.2 block and it's a hassle to go back and change it out. Especially with forged pistons and such.

Before you spend ANY money, you really should look at the dyno graphs of the 2.5L and 2.2L.

Most are taking from http://www.turbododge.com/forums/f4/...arts-here.html and http://www.relentlessracing.com/

You can EASILY tell which is 2.5 and 2.2. With the RPM range you want to use, you'll be better off with a 2.2 then a 2.5
(There were two 2.5 dyno that have a bit higher hp at high rpm but both blow their engines some time later, ... so... )


AJ's wagon, at 17psi with E85.


TurboShelby's Shelby Lancer at 19 psi (I believe) and E85


Shadow's 500hp car.


Pandemoniac


Seth


Warran

[2.216VTurbo]

Wait,did this thread get moved to the 2.2 Vs 2.5 debate section. When running right, the 2.5 will make plenty of power with that combonation. Did you completely block off that BOV yet as suggested? I still think your boost is going somewhere outside the motor... IC could have a split seam, could be a leaking hose, still have a charcoal canister? Could be leaking there also, bolt missing from IN manifold etc etc. Everything that holds boost pressure needs to be checked. What is your vacuum at idle, idling high or rough?

[cordes]

I know it's the exception to an extent, but Reeves runs a 2.5. I really don't think it should be the limiting factor here. I think it's a turbo trans combination.

[Keito]

I know it's the exception to an extent, but Reeves runs a 2.5. I really don't think it should be the limiting factor here. I think it's a turbo trans combination.

I'm not sure I agree.
I spool an HY 35 no problem with close to the same setup, I'm not sure how close the 50 to HY specs are.
I believe the OP has a better head, exhaust man than me, I have a +1 valve mild port head and stock ported exhaust mani

I have a friend who had a 2.5 with a 4000 stall converter and complained it was a dog
I bought the converter from him and had the stall changed to 3000 and run it with my 2.5 and I think it works fine
We told him the whole time to buy a lower stall converter, don't you want to be a few hundred RPMs less on the stall than peak torque?

Sorry guys, I think there's something else going on, cal maybe?
I run 87 electronics.

[mr b]

Wait,did this thread get moved to the 2.2 Vs 2.5 debate section. When running right, the 2.5 will make plenty of power with that combonation. Did you completely block off that BOV yet as suggested? I still think your boost is going somewhere outside the motor... IC could have a split seam, could be a leaking hose, still have a charcoal canister? Could be leaking there also, bolt missing from IN manifold etc etc. Everything that holds boost pressure needs to be checked. What is your vacuum at idle, idling high or rough?

Replumbed the bov, and checked all the connections. Tried 2 different cals very little change. are you suggesting completely blocking off the bov to check?

[tryingbe]

Spend that $100 and take your car to the dyno shop and find out what kind of torque and hp your 2.5L is putting out then decide from there.

If you're seeing steady 17psi throughout the RPM range, there isn't a leak big enough to make a huge difference.

[A.J.]

I think it's too big a turbo with an automatic. The 2800 is fine for the street. When you are going to realize the stall is wrong when you are brake boosting at the tree and you can't build any boost because the 2800 stall won't let you get to the point where you start to build your boost. You yourself said this set up was fine with a manual tranny.

Go back to 2.2L and the issue will disappear.

Not with an automatic, it will be even worse.

[mr b]

Contacted Hughes and will probably go with 3600 rpm stall

- - - Updated - - -

Spend that $100 and take your car to the dyno shop and find out what kind of torque and hp your 2.5L is putting out then decide from there.

If you're seeing steady 17psi throughout the RPM range, there isn't a leak big enough to make a huge difference.

Will use GTech today ; ) its kinda close.

[speedfreek500]

There is no way that build is a dog, Ya the turbo could be abit big with that converter. Has the cam timing and ing timing been set or adjusted at all to see if the power comes on sooner? Like posted before, strap it on the dyno and see where its at.

[tryingbe]

The way I understand this post...

I think it's too big a turbo with an automatic.

Lag isn't the issue.

I had a 5-speed transmission in it on a 2.2 block.

I had it rebuilt with a 2.5 block and swapped out to a fully built (auto) trans from Cindy. Now it feels like it has half the HP and torque.

AFR is perfect and 17 psi consistent boost.

He's complaint about having 17 psi of boost but lack of power and torque.

[A.J.]

Contacted Hughes and will probably go with 3600 rpm stall

I got my 3500 stall from them today. I'll be installing it next week. I'll let you know how it feels when I'm done.

He's complaint about having 17 psi of boost but lack of power and torque.

Just like me, it's the automatic. I've installed parts in stages so I know how each feels with an automatic. 2.2+Mitsu= fun to drive on the street. 2.2+.48 Garret= not fun to drive on the street. 2.5+.48 Garret= fun to drive on the street. 2.5+.63 Garret= not as fun to drive on the street but not as bad as 2.2+.48 Garret.

Just for shits and giggles, put the manual in if you have all the parts. It'll only cost you time and if that's it then great now you know. It's better than spending $500-$600 on a torque converter that MIGHT fix the problem.

I would also like to see some people chime in that have run big (bigger than stock) turbos with an A413/31TH automatic (and state as such) and get their impressions/opinions/thoughts.

[BoostedDrummer]

This motor put out 300 hp at the wheels when I had a 5-speed transmission in it on a 2.2 block. I had it rebuilt with a 2.5 block and swapped out to a fully built trans from Cindy. Now it feels like it has half the HP and torque.

So what you're saying is that you have a 2.2L head on a 2.5L block? I'm wondering if it's just not breathing right?

[4 l-bodies]

FWD MOTION Stage 3 Turbo 50 trim with a .63 housing.

What does this mean^^^? is it Forward Motion (FM) turbo or FWD performance turbo? Stage 3 turbine? Or E3 turbo? Plenty of guys have had good sucess running stage III with .48 AR housing in larger heavier cars. That will quicken spool quite a bit without spending a fortune on whole new turbo. That will also broaden powerband for your low RPM 2.5.

Cam timing stock? What does this mean? To me that means you haven't degreed it in. With resurfaced head and hopefully resurfaced deck of block, cam timing is definitely retarded. This can be a huge part of lazyness if it is retarded far enough. If you don't want/can't degree it in, advance camshaft 3-4 degrees for starters with adjustable cam pulley of offset keyways.

Do you know what ring and pinion are in your a413? 2.86 or 3.05? Transfer gear? .91 or 1.06? Final drive ratio? Winding up with a 2.60 final drive with a taller tire that is on a Spirit will make for a dog too.

Todd