is there really any room for improvement, will i gain any hp from further tuning? my A/F is between 11.5 and 12.1 thru my runs, what can i do to get more power, would pulling more timing get some?

 

Pulling more timing would lose power; pulling less timing would gain power at the possible expense of detonation, depending on what your R4 settings currently are. Your A/F ratio is where it should be.

You can increase HP with a more free flowing exhaust (headers, cats, cat-back, etc).

What numbers are you seeing and at what boost levels?

--Steve

 

with my 9lb pulley im getting about 10 more thru the runs, but at around 5300 rpms there is a dip in the hp and the car drops a little rich at the same time, so the car hits the rev limiter before catching up so im actually getting a lower max hp number.

i have test pipes and the injen exhaust

1psi @ 2450
2psi @ 3350 172hp
3psi @ 4000 210hp
4psi @ 4500 243hp
5pdi @ 5000 283hp
6psi @ 5500 303hp
7psi @ 5900 317hp
8psi @ 6500 352hp
9psi @ 6890 ??? dyno cuts off at 6600 for some odd reason.

the dip i mention starts at 5300 and it never fully recovers, if it did it would be awesome, near 400,

 

have you did any timing adjustsments at all ? If not , you can gain another 10 to 15 hp up top and get rid of that dip

 

How much timing are your retarding?
Also, how rich are you after 5500rpm?

Shoot for 11.5 a/f across the board and the idea is to retard timing just enough to avoid any traces of detonation in gears 1-5.

if you accomplish that, there is no more safe HP to be made. As mentioned, headers, cams, and other areas can get you more safe WHP, but from where you are now...you are near the max without increasing boost further.

 

im wondering if you arent experiening some micro-slip on the belt???

what type/size of belt areya using, btw??

SMS

 

gq-

im pulling 2 up until about 4000, then it goes to 4 until 6000, then 6 until 8000. a pic is below.

im using the gates 93" belt. i might need to tighten it but my boost numbers are good, so it shouldnt be slip.

 

So near redline, is the total timing retard 6 degrees? If so, your timing should be pretty good. Just try to clean up that rich dip and smooth it out...you might pick up a few WHP.

 

yeah at redline the timing is -6, whats weird is that the dyno shuts off way early @ about 6500, i dont know why it does that, anyway,

the red and blue lines on the dyno were the first 2 runs, the green one is the third one where i added a little fuel to richen it up some, actually more than i wanted, and it didnt help at all on the hp dip.

you think i should pull some fuel instead of add it, would that help.

there was a guy at the dyno that mainly works on mustangs, who was watching my runs, he said the dip looks like the factory knock sensor is pulling some timing on its own, he told me to pull a little more, but i dont know if i trust him. although he was driving a new roush stage 3 with some nice engine work pushing out about 400hp at LOW boost (6.6psi and he was about to double it, damn it sounded good)

 

My Vortech curve has always had a similar flat spot around 5500 rpms.

--Steve

 

none of my previous runs did, only when i installed the 9lb pulley did it do this.

 

The dip at 5500 is from our CVTC variable cam.

 

ACP--is there anything i can do about it?

 

Just went back to look at my best dyno run... sorry for the poor image, this is from a scanned printout.

Still, you can see a very slight dip right before 5500rpm. I think this is the same thing tig488 is hitting, but as you can tell my dip is not as severe. I'm sure this is something you can adjust for if you keep working on it.

 

oops... forgot the graph...

 

if things were linear, or even a little less than linear, i should be much higher, especially if it went up to 6800rpms, something is causing me to lose a lot of power, i need a good tuner.

damn mcduck thats awesome!

 

I do NOT think this is a tuning issue.

If you look at mcduck's N/A graph you'll see that it follows a pretty straight line. But that's only because he has LOTS of mods that give him upper end power. The typical N/A graph starts falling/leveling off above 5500 rpms.

If you had a Crawford plenum, aggressive cams, high flow cats, headers, and a free flow exhaust I'll bet your graph would more closely follow a straight line like his does.

--Steve

 

The only thing I would point out is that you should be pulling timing more evenly. The way R4 works, you are pulling 6 degrees at 5501 rpms. That's arguably more than you need on 93 octane. I would vote for something like this for timing retard:

4500 1 degree
5000 2 degrees
5500 3 degrees
6000 4 degrees
6500 5 degrees
7000 6 degrees

The net affect of this is 1 degree beginning at 4501, ramping up smoothly to 6 degrees at 6501. Smooth changes in retard are better than the jump changes you have right now.

This change won't make your line straight, but it will add a bit more power.

--Steve

 

I agree with Zimbo in part... my lack of high end drop off is mostly due to the Crawford Plenum and Nismo Cams... both of these items help free up intake breathing. Thus, easier to flow more air/fuel mix.

The part I still question is the dip itself. There must be some way to adjust the tuning from 5500 to 6250rpm so that instead of a dip, you have a smoother line running between those peaks. Otherwise, I think I would have the same, or a more pronounced, dip.

The question becomes, is it worth extra tuning time and cost to level out that dip. You won't be gaining a spectacular amount of power. Sure, you increase your area under the curve a little, but do you feel that dip in the powerband when you drive? Or does the car just feel like its pulling strong all the way to redline. If the car feels good, I wouldn't waste time trying to decipher the dip. If you feel a noticable (negative) change in the way the car pulls when you hit the dip range, I'd keep working on it.

 

its hard to tell whether i feel it or not, i think i do but it might just be in my head, right now the car is strong and with no problems, i dont feel like spending money on the dyno until i find somebody familiar with the software.

i might get a crawford plenum, but id still be without the cams and headers, i have test pipes and exhaust already, plus ill try your timing solution zimbo,

oh yeah zimbo right now im using one of your maps with a little modification to the fuel, remember i was using a while back and made the most power with it but was REAL rich, not the A/F is almost perfect, i wonder what #s im getting now.

thanks guys.

you wouldnt mind letting me look over your maps would you mcduck?