here is a copy of my dyno with rmb and ebay chips. my car is a 1986.5 5speed. if you see around 3,000 rpm it seems to run real rich but there is no loss of power .. any idea how this can be corrected ?
thanks
v-tach

 

DO you have a regular dyno sheet, that one is hard to read?

 

Looks more to me like it's running real lean from 3500 to 4500, with a big loss in power. But what do I know?

 

Peak at 3K? That doesn't look right.

 

Sure. Throw away the eBay chips and tune it right with a piggyback.

 

That is the torque curve, and yes for an 85 or 86, peak torque is usually around 3000 rpm.

 

Here is my dyno with the exact same set up; RMB and aftermarket chips.


Max torque is at around 4500 rpms not 3000.


Here is my a/f chart. Mine is the line in red.

 

You are running lean from mid-3K to about 5.5k rpm. Running lean at the start of a run is normal.
Your rich spike at 3k is weird. If I was forced to stab at a diagnosis I'd point a finger at low fuel pressure for the lean condition. But, a non-operational WOT switch (and perhaps a crufty O2 sensor) might account for both the lean condition and the rich spike.

 

and here is the hp curve..

 

shane
my afr curve is almost the same as yours - i guess that is okay - i thought maybe there was a problem with the chips but defintely no loss in power...
thanks
v-tach

 

That is definitely strange. Look at Shane's -- his is making 270 ft/lbs at 5K, yours is making 220-ish. I hadn't looked at the scale before, just didn't think it looked like an 85.5 curve.

 

There is a characteristic hump that starts in about the mid 2000s for 85 and 86 engines that is missing from Shane's dyno.

If Shane's dyno run had started at 2000 RPM, not 3000, we just might have seen a peak closer to 3000. Towards the end of our owners manual is a graph of HP and torque. Our engines try hard to beat the early torque peak, some of ours succeed in doing so but I wouldn't be surprised if most do not.

What seems to be missing from V-tachs dyno is RPMS higher than 6048. Chips usually increase rev limiters to @ 6500. If it were me, I would have liked to take RPMS up to at least 6200 so that you can see the downhill part of the HP curve. It is useful to see how it drops off. On the other hand, I cannot say anything bad about someone that doesn't want to overrev their engine. Conservitive approaches to cars can lead to longevity.

Vtach's results are high enough above stock to indicate that the chips are doing something for him.

So, where does one buy a piggy back? Anyone have anything they would like to show that proves the potential and $$$ value of a piggyback device?

Thanks