I see you have a similar setup. Unless of course you have heads and cam? Is 420 RWHP too low because I thought I would be about where you are at? Heres my original post.

Before any mods my car dynoed at 300 RWHP. A couple months ago I installed a procharger 8psi kit with the D-1 compressor. This kit supposedly gives 560 HP at the flywheel on a completely stock F-body. I then installed Mac Headers and an offroad Y pipe. There is also an exhaust cutout after the Y pipe. These aren’t my only mods but they're probably the only ones that would affect my situation. I had my car dynoed at Car Craft on Sunday 7-21. Although the weather conditions were less than good to say the least it only put out 419 RWHP without Nitrous. 560HP with a 15% drivetrain loss would be about 476 to the rear. I was expecting at least 450 plus whatever the headers added but needless to say I'm slightly disappointed. Could this be a computer-tuning problem? I do not have O2 sims but I was told this only affects the check engine light and does not affect tuning. When I had the car dynoed before the charger with a 150 shot I was at 440 RW with no headers. What is going on here? The Mac headers required me to remove my EGR system. They made the headers for 98-99 & 01-02 models. So I just removed it all and plugged the hole in the manifold with an expansion plug. I don’t know if maybe this could have also messed up some tuning parameter but I wouldn’t think so. EGR is not supposed to function at WOT anyway. Before the headers I was at 8-9 psi with the 3.20 pulley. It would occasionally spike to 10psi for a split second. Now with headers I am at 7-8 psi with the split second 9psi spike. I’m just trying to give you all the info because I have no idea what the problem is. I’d like to figure it out instead of just going to the 3.0 pulley or adding more N2O. What kind of boost increase do you get going to a 3.0” from a 3.20”? Just curious. My fuel pressure never drops below 60psi and at idle or cruising its at about 62-63 psi. I have a 255 lph inline booster pump with 42.5 # injectors. My computer tuning was done by superchips. The dyno was done in 4th gear. I always thought they were done in 3rd but that couldn’t be responsible for the big gap in numbers. I think I need some good on the dyno tuning but can that really make that much of a difference? Any ideas?

 

I'm making 486 RWHP and 487 RWTQ. Optimized, I might would make a tad over 500 RWHP (maybe 510 or so).
That is with 42# injectors, MAC headers/y-pipe, SY3500 Converter and Superchips Programming.
I do not have aftermarket heads/cam.

I am running the Aeromotive Pump, but my understanding is that it is 105gph (~ 420 lph?).
My Fuel Pressure guage reads about 58 PSI idling, about 56 PSI cruising and the aux pump maintains that 56 PSI when I WOT it.

With Headers I am at 10 PSI of boost, with an 11 PSI spike, when my belt is tight. I average 9.5 to 10 PSI as it wears.

I was at 12 PSI boost with a 13 PSI spike before the headers/y-pipe.

What you haven't told me is at what RPMs you are making that horsepower.

What is your Max RWHP at what RPMs and what is your Max RWTQ at what RPMs?
My RWHP # was at 6400 RPMs, max RWTQ was around 5500 RPMs.

My pre-SC dyno (with SY3500) was around 297 RWHP / 345 RWTQ).

What is your A/F ratio? Too rich a mixture could kill your power. Superchips had mine too rich the first time before I changed pulleys and it's too rich again because of the headers mod.

The Dyno Shop SHOULD do the pull in 3rd gear for an A4 and 4th gear for an M6 because these gears present the smoothest power curve, which is best suited for consistency in tuning. Mine was done in 3rd gear (an A4).

Mull my info over and see if it sparks any ideas or raises other questions.

Good luck!

 

Thanks for your info. That does spark some ideas. I'm at work right now so I dont have my dyno graph but I think my max HP was at about 5300 RPMs and max torque was around 4500 RPMs. When I first saw that graph I was a little confused because I thought my max HP would be where my max boost is at. Is that how it works? Maybe my belt slips once my boost starts climbing. Others have told me that if the crank isnt keyed or something that the ATI pulley can slip.

What is your rev limiter set at? Mine is still at 6200.

Are you running the 3.20 inch pulley or the 3.00 because thats a lot of boost you're getting if its a 3.20" ?

Can Superchips adjust fuel pressure with the programer? Maybe I have too much.

I also put headers and the no cat Y pipe on after I got my programming so thats not configured.

About the lean/rich situation. I'm pretty sure I'm running way to rich. What ratio should they set it for? 12.5:1 ? 13:1 ? I dont want to be lean but just a little richer than Stoich. Have no idea how to spell that.

Thanks for your help. Its hard to talk to others about this problem because they dont have a procharger so they all go "well you should be at about 400 - 420. Grrr.

 

12.1:1 is a well accepted a/f to shoot for with a FI car.

 

That's part of your problem... rev limiter at 6200 is too low. Set the Rev limter to at least 6600 and try to have the car shift around 6300 to 6400.

(In case you're skeered <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> , my rev limiter is at 6800 and shifts anywhere from 6400 to 6600 depending on how much it spins and whether I have the 25.65" or the 26.0" tire on.

The boost gets a couple lbs higher past 6000 RPMs.
Just for reference, when I had the 4.10" pulley I was 4 to 5 PSI between 3500 to 6000 RPM. As it hit 6300 to 6400 RPMs, it would peak at 7 PSI. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

With the 3.20" pulley, I hit about 7 or 8 PSI nearly instantly, and peaked at 10 PSI, around 6400 RPMs.

On a blown motor, your A/F should be slightly rich up to peak Torque and go leaner as you approach max HP to be no leaner than 12.0 or 12.2, thereabouts.

Max Torque around 4500 RPMs doesn't make sense, though. Your boost seems low at that point for torque not to still be rising. Check your dyno and tell me for sure what your peak HP/TQ are at what rpms before we go any further.

I still don't know if you are A4 or M6, either... and if A4, what kind of stall. I'm assuming now that you are M6... ALSO, what rear-end ratio?That's going to make a difference, too.

 

I'll check my graph when I get home. I get out of here in less than an hour. My car is a M6 with 3.42 gears.

How can I get superchips to do the program correctly? Everybody tells me they're idiots. What would they charge to optimize the custom program I already paid nearly $700 for?

 

Allright I checked my graph. Torque peaked at 4700 and HP at 5300. Hmmmm

 

If you changed anything (more or less mods), I think it's a $150.00 re-tune fee. But they shouldn't charge ANYTHING if the tune is not right.

What does your dyno say your A/F ratio is? (It's sometimes in 500 RPM increments.)

 

BTW, I heard they only do chassis dyno tunes with shops that have a modem hook-up now. Maybe you shhould see if they'll give you a break on one of those. You're SURE to get the best out of it then.

 

I dont know what my A/F is because they didnt do a A/F reading. Do you think that my HP is dropping off because of belt slippage?

 

If it was me I would do what I did and spend the 550 and get ls1 edit.

 

I actually am in the process of buying a laptop and LS1edit. But I dont know if I would be able to properly tune the car for max efficiency with the knowledge I have. Does the program come with detailed instructions? Would I be able to do just as much as superchips could do?

 

Just tighten that belt down another turn or two and see what happens. If the boost doesn't go up, you can always take 4 minutes and slacken it back up. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Your peak power/torque is too low at that rpms. If it STAYS that low and there is nothing wrong with your motor or SC kit installation (or fueling), your tune is a good candidate. BUT, you need an A/F graph/table.

Do you have autotap? Maybe we could get an idea of your approx A/F by checking your Bank 1 O2's.

 

I was going to buy autotap but then everybody was saying how good ls1edit is so I'm just going to get that instead. My buddy works at a shop with scan tools. Those can give me my codes but can they read my A/F from my O2s? I will tighten that belt and run her this friday but I doubt I'll be able to tell a big difference but I'll see what the boost gauge does. Right now it seems to stay at 7psi forever until I get to like 5800 rpms. I'll check it for wear and tighten her down. At this point it looks like it must be comp tuning unless its the belt. I just hope the ls1edit manual explains everything in full detail on how to modify settings for different things. Heres a list of possible improvements.

-Check A/F and adjust.
-Check timing because I bet Superchips retarded it even though I said not to. Return that to stock settings.
-Raise rev limiter to 6600

I wish I knew something about fuel maps. What else would I adjust to fine tune it? That doesnt seem like enough to justify the low power output. I guess depending on how bad those settings actually are. What needs to be adjusted besides A/F to compensate for headers and no cats?

 

What kind of dyno was it? Were the numbers corrected?

 

I forget the exact name but it was a dynojet. All I got was a graph printout. I didnt get a table. The graph did not say corrected anywhere on it.

 

I know nothing about the Procharger setup, so I will just speak to tuning...

1) LS1Edit is not a scan tool, all it does is download and upload programs to your stock computer. You will need a scan tool (AutoTap, EASE, etc.) in order to accurately tune your car.

2) Stock o2 sensors are no good for WOT tuning...you are going to need a dyno with a WB o2 or you are going to have to buy a stand-alone WB for ~900.

3) Your friend might be able to look at codes with a scan tool or look at readings for a short period of time, but you are going to need something that has the ability to do logging so that you can tune it (again EASE or AutoTap).

Good Luck,

Scott

 

While I agree O2 sensors are not an absolute A/F guage, I disagree with the statement that "they are no good for WOT tuning".

WHile not an absolute indication, certain values of the forward bank of the O2 sensors can indicate a realtive richness or lean condition. Autotap comes in handy for this.

If O2's were, say in the .960-.980 range, you are likely running too rich. If they were around .810-.850, you are likely too lean.

This is a VERY handy parameter to monitor, unless you want to stay at the dyno all the time, or buy a $1000 A/F monitoring tool.

 

What did you peak at before the supercharger BlackLS1TA? I peak at exactly 6000rpms with a 224/228 cam.. I think my peak should be higher than that.

 

From what I recall, it shifted just a couple hundred RPMs lower than where it does now.. maybe around 6300 RPMs. There is a couple pounds boost difference between 5900 RPMs and 6300 or 6400 RPMs.