Here is my dyno sheet from a while back. I am posting it because a friend and I were talking about it.

We are scratching our heads on why the torque is so low. And horsepower is lower than I expected also.

91 TII
-Atkins Mild Streetport
-Majestic Turbo Upgrade (Not sure of compessor upgrade but the turbine was clipped 4 or 8 deg.)
-Bonez Downpipe to a Bonez Hi Flow Cat (2.5")
-Apexi' N1 Duals
-Apexi' cone filter

FUEL
-720CC secondaries
-Walbaro 255 pump
-Rewired pump electrical wires

IGNITON
-Crappy Wires
-MSD 6A on leadings
-New plugs installed before the run (that burned me)

The conditions were less than ideal. The dyon recorded 98F on the airtemp. The site is about 500' above sea level.

My intercooler was so hot after a run you could not touch the fins. We were spraying water on it for several minutes before each run.

One thing I like about the dyno is it makes power right up to 7800rpm.

Things I don't like. The low torque/hp.

A/F? Well, it was a wideband. However, it was installed after the cat and it was pointing into the exhaust stream. From what I hear that is the wrong way to use one. Since then I have installed a Techedge DIY WB but havent had time to play with it.

My thoughts are the cat is destroyed. The car was running rich. The reason I think this is because after one good flogging session the DP and Cat were glowing. Anouther friend thinks it is a boost leak.

Help? Ideas?

James

 

So what was the a/f ratio the wideband was indicating? Also, do you have any compression numbers of your motor? The torque is awfully low.

 

Right now according to the Techedge at WOT it is normally 12:1 and richer.

At the time the wideband was worthless.

I need to do a compression check. I hope it isn't but one would be needed just to check

 

Im not sure where the problem could be, but a year ago I dynoed my car;

87 Turbo
150k miles on motor
RB turbo back
S5 turbo w/ upgraded compressor
Stock intake
Stock intercooler.

I was running 6 psi of boost the entire time and the car was tuned to about ~11.2:1 af using an safc. Fuel mods only Walbro in take fuel pump.

My car pulled a peak HP value of 203.5 hp, and 178 tq. So I was about 20tq above you. The outside temperature was about 65 degrees that day but its hard for me to remember.

 

How is your clutch doing????

 

It is a ACT Street/Strip clutch with no slip.

Found the turbo details

TO4E-46
Ported wastegate
8° Exhaust clip

James

 

I had the opposite problem as you. I have about the same mods and My hp was 200 with 225 torque. My turbo was shot them, so I reached max power at 4k RPMS. Your torque number is way too low.

 

what boost are you pushing?

 

 

To me from the look of that torque curve the 2ndaries are mis-tuned or too large.

 

Icemark:

That is an intresting thought. I do like that idea. I will make sure I datalog my AFRs on the runs. See what I can get. I believe I can post my datalogs.

I will have a chance to trouble shoot the car in July. Prob. wont be able to take it to a dyno.

Keep em coming guys!

Anybody know how to get a hold of ReTed?

James

 

And that run was about 9psi

James

 

I would take your cat out and take a look.

or replace it

and check your timming.

downpipe / cat shoudln't be glowing

 

I was going to just take it off and do a quick run with dp and the pipe that goes to the cat.

I should not melt anything right?

James

 

I don't think a wideband will work behind a cat. I would suggest some tuning with the wideband before the cat. Intuition tells me that the car was running rich, though that may not be a bad thing with your intake temps so high that the intercooler is too hot to touch. Time for some water injection.

 

At the dyno the wideband was aft of the cat. My wideband is in the midle of that pipe between the dp and cat.

I think I am gonna order that midpipe from rx7.com so i can trouble shoot the cat.

Can you look inside one and tell it is messed up? I guess i could hit it with a hammer and see if anything bounces around.

James

 

if you take the cat off. and stick a light at the other end. if you don't see any light. then it's pretty cloged

 

Bigger injectors and fuel pump with no control and you're wonderering why power is down? Rich mixtures will always result in less power. You need to get it tuned properly, meaning either a fuel computer or a programmable EMS. The cat may be clogged too, but I'd say that's your main problem right there. That's obviously a power killer on a dyno, however the airflow through the IC will be totally different when you're on the road. That's the way it's usually done on a chassis dyno. Shouldn't cause any problem even with a cat.

 

I have a S-AFC right now. However, it really wasn't tuned. Right now it is set at zero and still running 12:1 and lower.

James

 

Shouldn't you have done that while on the dyno?

 

LOL, yeah

We made it rich as hell. I don't the settings but it was +15% above 5000rpm. It just wasn't right at the dyno. I don't know man.

Want to get it datalogged with my wideband.

 

Holy moly, it needed to be minus 13% just to lean it back to factory mixtures! Why did you go richer?

 

That is what his wideband was saying man.

James

 

well, i hope you get your car to work at its optimum

 

I hope so man! Thanks!

James