So I went down to KD rotary today for some dyno tuning. I was worried at first, because over the phone they really don't sound on top of things. But, I had a few friends who strongly recommended them, so I went. Turns out Dave the owner is a great guy. Great experience. He gives a new meaning to busy, working from 7am to midnight 7 days a week. He's a machine, I don't know how he does it. He has over 50 rx7's there and just one other mechanic. I can imagine why it would be difficult to keep track of different customers.

The tuning had good and bad results, it's never just good, I wish I knew why. I made 287whp at 7psi. Which is awesome, very happy with that. I have to give credit for that to PFS though. It was their map that made that power. But, when we tried to crank up the boost it wouldn't budge. We turned the boost controller up to 12psi, but virtually no change, it stayed at 7psi. We decided to tap a boost gauge into the fitting in the cast elbow on the turbo outlet to see what the boost was there. Turned out to be 13psi. So, I have a 6psi loss between the turbo outlet and the throttle body where my boost gauge is tapped. So obviously we assume it is a leak. We looked, couldn't find one, so plugged the suction pipe at the air filter and the up-pipe at the throttle body and pumped the intake tract full of air. It held pressure perfectly. So no way there was a leak there. The only thing Dave could think of was that I have a cracked intake manifold, but that didn't evidence itself in any other way. The car holds a solid 20" vacuum, and no real idle problems. Any other ideas on what this could be?

But I have to say 287whp feels pretty good. You really have to get used to driving the car again, 1st and 2nd gear fly by!

 

Zoomzoom_8 had a bent throttle body, thread here . But it should've showed up in your leak test if you had that.
Maybe a hose coupler is letting air out OVER 7psi? How much air did you pressurize it too on your leak test?

 

287 whp at 7psi is nuts. Thats really good.
As far as why its not boosting over 7psi... i have no idea. I'll let the more experienced rotor heads answer this one.

-hS

 

I just reread your post and realized you plugged the up-pipe at the throttle body, SO it could be the throttle body that's the prob or the intake manifold which Dave suggested.

 

Congrats on the numbers dude. That is still quite an odd problem you have because you are able to hold vaccum solid.

What did your boost fall down to at high rpm?

 

It held a solid 7psi till redline.

One other thing that occured to me today is that I have a cel that I never pulled the codes for. I know certain cel's can restrict the throttle from opening beyond a certain percentage. I wonder if that could be happening?

At the time we only pressurized to 5psi, figuring if it held that it should be fine. But, I think I'm going to redo it and pressurize it up to 10 or so psi

 

Congrats on the 287rwhp, sounds like you will join the 300rwhp club very soon! What was the torque? Did you save any of the data logs from the Interceptor-X? I would like to see the boost curve,AFR and rpm that was logged. Check the transition coupler at the bottom of the throttle body tube, Loube's tore but you could not see it unless you removed the coupler from the car. The boost would spike and then drop and hold ~7 psi on the dyno.

 

nice run just the same, hope you solve the issue soon

 

Congrats on the numbers, you will be a 300 rwhp member soon.

287 is great at 7psi
Hope you get the boost discrepancy fixed and look forwrad to your findings.
In the meantime, go enjoy your tuned 8.....Have fun!

 

Yup, I'm sure once you fix that boost problem you'll be over 300whp in no time. As far as the turbo itself, did you get it upgraded when you got it fixed?

 

No, I decided to stick with the stock Greddy turbo. I thought about the Bullseye upgrade. But there wasn't any feedback on it yet. Without dyno charts, or boost plots I couldn't justify spending that kinda money. I had scott port out my wastegate though, and he also smoothed out the inside of the cast elbow for the turbo outlet.

I tried to pull my codes today, but the OBD scanner kept giving an error message saying it couldn't connect. I remember the dealer had this problem about 2 months ago on my car as well. I thought they had fixed it, but I guess not. Tomorrow I'm going to disconnect the Interceptor and try again. Has anyone else had a problem pulling codes with the Interceptor connected?

 

Torque was 220ftlbs. Dave had also seen problems with that reducer, so that was the first thing we checked.

I don't have any of the logs, but Dave saved a bunch. I can ask him for them, or send you a log from a street run.

 

I haven't had any problems pulling codes with the interceptor.

 

I had trouble with my OBD scan when I first got it---on some cars the connector does not make contact on all pins,I used dielectric grease on the pins and it connected

 

Which tool are you two using? I have the Scanalizer and haven't had any problems thus far. Not sure if that woule have anything to do with it or not.

 

nice numbers. hope u fix ur leak

 

Well, I believe the problem is fixed. There was nothing wrong. I believe the shop was just using to low of a duty cycle in the boost controller settings. I can't say this for sure, because I didn't see all of the changes they were making.

I seem to remember that Lschavio had a problem where he couldn't go above 7psi on the dyno, but did fine on the street, so maybe they were adjusting the right thing and it just wouldn't hit it on the dyno. But it definitely hits it now. AFR's look fairly rich at 9psi around 10.5, might be because it is so hot today though. I'll wait till a colder day and see if they settle back around 11.5.

But I have a boost gauge still installed at the turbo outlet and noticed it appears that I still have around a 4psi pressure drop throughout the piping, which is fairly high. I wonder if this is maybe just the way the kit is or if maybe I still have a leak. Can someone else put a boost gauge there and measure the difference. If it is a characteristic of the kit's design, such as the intercooler being too small, then by improving that we may be able to get some more power out of the kit.

I want to get some more data logs tomorrow though to verify this loss. It could just be due to the difference in the two gauges I am using.