skotx

Took my car to the dyno and was baffled by the results: 227.8 RWHP and 204.7 torque. Sounds like a stock car right, maybe with an exhaust? Not quite: FMIC, DP, stock cat, CB, upgraded sequential turbos, RE intake, Pettit ECU. Some of my parameters are unknown, as I do not know how the previous owner had the ECU tuned. I do know it's tuned for a freeflow exhaust, so that partially explains my rich condition (I'm running with the cat). Also I'm still in the process of finding out exactly what he did to the turbos.

Ok, so that's all fine and dandy, but here's some more pertinent (and interesting) info. At the 4500 RPM changeover my HP actually decreased by about 15 points in all three pulls. My best pull saw it go from 178.3 to 164.9 at 4600 and then peak at 227.8 at 6200. From there it's downhill all the way to 8000. Ok, so you've got a boost problem, check your hoses, dork. Problem is, boost gauge is showing pretty close to 10-8-10. Could it still be a hose? I hate to ask without having checked any of them yet, but I was curious if anyone had had a similar experience.

Thanks a lot.

-Scott

Marshall

Do you have a picture of the dyno sheet?

Red-Rx7

Could be many things.. But like Marshal said: Lets see the dyno sheet.

I had ignition problems once (bad plugs). Dyno sheet was whacky. Made some weird 240 rwhp. Then I changed the plugs and made 344 rwhp.

Mike

skotx

I sure don't. I'll try to get it scanned ASAP and put it up, but probably won't be able to before tomorrow.

beast TT

I'll agree that ignition is a good place to check for
the cause of losing hp on a dyno run in consistqnt
runs.

But turn your boost up....Your runnin 10 psi??????

kwikrx7

Yeah, you're right - stock FD with one mod would be around 225-230 rwhp. If you're showing 10-8-10 then a leak doesn't sound right. You'd be surprised what bad plugs can do. Have you changed them lately with the wires?

cewrx7r1

iTrader: (2)

That stock cat is the real problem. A real power eater. You can't put more in if you can't take it out! First rule of rotary modification.

skotx

Here's a pic of the dyno sheet. I appreciate all of your input so far, I'll definitely take it into consideration for the next run. The cat will be gone by then too (since I've got a midpipe sitting on my floor! ).

Styk33

It could be igntion like people are saying, it looks like there is a little break up above 6k. You also are running fairly lean in the mid RPM ranges and then go to real rich in the upper RPM ranges. Running real rich does take a toll on the cat, although I am not sure how rich or how long it takes to kill it.

Check your plugs, make sure your wires are okay. What were your coolant temps like on the dyno? If your temps are in the 220F range you lose a lot of power compared to 180F. There are a ton of variables that can cause you to make less power.

No matter what anyone says, there is nothing wrong with running 10psi on the dyno. I ran 7psi last time I was on the dyno with the stock twins. Although I put down more power than you

Marshall

The AF ratio on that green run is a motor killer! Is that correct!? I'd be surprised if it wasn't damaged already.

skotx

No, I should've pointed that out. On the third and last run, the green one, something happened with the sensor and it got knocked out of place.

I'm finding a few 3rd gen dyno sheets on the net that are great for comparison, but I don't know what a good AF line should look like. What's a good target number? Does that target change with boost level? And is it a straight line, or a slowly descending line?

Unfortunately I don't have an aftermarket gauge, so I was relying on the stock one. It didn't seem to go much above the halfway point though, and I was running with the fan mod plus a floor fan.

I've got the Power FC coming my way shortly, so I'm looking forward to having more control over my car.

Thanks again.

Kurgan

11.8:1 is where you want to be in the AFR for boost. Cruising at around 12.5:1 and idle around 13.5:1 People will tell you different, but these numbers are pretty darn close.

Wade

iTrader: (1)

Your a:f looks fine, just like it should with a stock ECU or modified stock ECU. You aren't running so rich to kill all your power though - stock cars/ECUs run around 10:1. Checking your plugs and ignition is about the only thing I can think of to check.

Wade