My '97 is almost stock.

I have a Down-pipe, 3" Stainless System with a hi-flow Cat and a Rota-Flow.

Had it on the Dyno the other week, but it was quickly apparent that she is leaning out at around 5000RPM, and power dropped dramatically at that point (155RWKW).

I know the dangers of running lean, so have basically parked it pending the arrival/install of an E11.

BUT I was thinking about it, and I'm not so sure the Haltech is gonna fix this by itself??

I was thinking that with such mild mods, surely the factory ECU should be able to adjust itself to supply enough fuel? We are talking an additional 10RWKW for the Down-Pipe, and (maybe??) another 10-15 for the free-flowing exhaust.

How do I determine where my problem really is? IE Fuel Pump, Injectors, ????

Or am I wrong, and the Haltech is most likely all I'll need at this stage?

 

Exactly how lean is it? It should be fine with just those mods and STOCK BOOST.

 

I can't find the darned Dyno Sheet at the moment

But at 5K the power actually dropped off. Boost at the time was 10lbs.

 

When you run lean on a dyno, your power curve will go up, not down.

 

Sounds like you might have hit fuel cut on the stock ECU.

 

How does that work out??

 

Well, that was what I thought originally, which is why I ordered the E11... but the more I think about it, the less sure I am... it seems to be me that there should be quite a bit more in it yet??

Which is why I'm asking how I can accurately narrow down the cause..

 

Here is the chart for fuel cut:

RPM ABS. CUT OFF(PSI) SEA LEVEL CUT OFF(PSI)

1000 26.5 11.8
1500 26.5 11.8
2000 26.5 11.8
2500 26.5 11.8
3000 26.9 12.2
3500 27.1 12.4
4000 27.5 12.8
4500 28.0 13.3
5000 26.9 12.2
5500 26.0 11.3
6000 25.8 11.1
6500 25.4 10.7
7000 25.4 10.7

So, it would help to see the dyno chart.

I'm not sure how those numbers are affected based on Sea Level. Also keep in mind that fuel cut doesn't happen instantaniously (as it would cut fuel on ever single boost spike). So if you were peaking at 12 PSI in the lower RPMs, I'm sure it's possible that by the time fuel cut happened that the boost might have settled back down.

What type of boost gauge are you using?

 

You make more power when your lean. "leaner is meaner"......but you also blow up when lean. Double edged sword. Get the Haltech, upgrade your fuel pump, changed fuel filter, upgrade secondary injectors and you'll be set.

 

ever hear the saying your motor never felt better than the second before it popped?! ErnieT is right. you should not have lost power. post the sheet.

 

OK.. so I was more likely running out of fuel than running lean??

I finally found the dyno sheet... I'll attach it next message..

 

I'll attach the Dyno sheet now.. (finally found it!)

I'm using an Autometer Boost Guage.

 

Very possible especially if you started running over 10psi with the stock ecu. Get yourself the E11K, the fuel pump, injectors and be safe. Good luck....

 

Thanks Ernie (and everyone who answered).. your advice is much appreciated..

Have a Happy New Year!

Cheers,
Dave

 

what's an E11 K?

 

The newest Haltech ECU.

Haltech Website