99mph in the 1/4 with 8psi?

[46addict]

As the title says, my last outings at the track have been disappointing. My car is Procharged with the 4.13" pulley and I'm seeing 8psi on the gauge. With a 2.2 60' time I trapped the same speeds as a stock 3v. Didn't matter if ambient temp was 75 degrees or 95 degrees. It dynoed at 429/380 and is tuned for 9.7psi. Target AFR is 11.6 and it dips below 12.0 from 3500rpm. I noticed by the time I see 8-9psi it's time to shift, so on average the engine sees maybe 5-6psi down the track.

Comparing my dyno graphs from when the car was full bolt on + cams versus now, the blower doesn't begin doing its thing until 4800rpm. Rev limiter is set to 6200 for the sake of stock internals. I bought this blower kit used from a member here, and from searching his threads, he had the same issue. His NA + nitrous times were faster than he was with the blower.

My intercooler piping has a provision for a wastegate, right next to the bypass valve. I ordered a gate with a 10lb spring and I want to try it with the 3.40" pulley. I believe it's the smallest pulley available for the 8 rib P1SC. With my IAT already at 140+ during a run (that's almost 2x ambient), this is probably a stupid idea without upgrading the IC or adding meth so that is going on the list. But I want to check other things first and see if anything broken/wrong can be fixed. I know I need traction but there's no sense in buying drag tires/wheels if my car has no power to put down.

My tuner had me datalog and he has the timing at 20 degrees and I saw 93% pump duty cycle. I did the BAP wiring upgrade using 10 gauge power& ground wires after seeing that. I haven't done a log afterward yet to compare. Is there anything else I can check before I go to my last ditch solution? How tight can I crank the belt without breaking something?

 

[stkjock]

Frankly IMHO, you're not getting the times as you're not using the blower / power curve effectively, you must be shifting at 6000? Max?

My 06 at 430 whp would trap 112-114, I shifted at 6500 with a limiter at 6700, stock long block.

https://youtu.be/nvvGvcA0QrA

 

[05stroker]

I remember my first Procharged trip to the track. I was at 425/380 on 8psi and I traped 108 mph and I was pissed!

What does the boost curve look like? Belt slip?

 

[redfirepearlgt]

A guy here local has a procharger setup. Car makes 750+ on teh dyno but only runs a best of 10.78. Leaves hard out of the hole but then falls on its face on the big end. His IAT temps are too high and that is obviously pulling a crap load of timing out at mid track. He's upsized the H.E. relocated the IAT/MAF and even lowered the boost from 22 to 20psi and is now getting ready to add the meth injection to get the IAT's down. I can't remember what his IAT temps are but they are the source of his problem. He's also considering going to water cooled vice air-air.

He ever gets those IAT's down it will be flying. He's gota WOT N2MB on the setup (scares the crap out of you when he no loft shifts) with a T56 magnum 6 speed, full forged internals, cams, LT's, the whole ball of wax.

 

[46addict]

Frankly IMHO, you're not getting the times as you're not using the blower / power curve effectively, you must be shifting at 6000? Max?

My 06 at 430 whp would trap 112-114, I shifted at 6500 with a limiter at 6700, stock long block.

https://youtu.be/nvvGvcA0QrA

The rev limiter is set to 6200 so that's where I shift. Maybe I'll get it raised and try again.

I remember my first Procharged trip to the track. I was at 425/380 on 8psi and I traped 108 mph and I was pissed!

What does the boost curve look like? Belt slip?

Boost curve on the dyno sheet is a steady line starting from 3psi at 3500rpm and makes it to 9psi by 6500. I need to look at it again to verify.

A guy here local has a procharger setup. Car makes 750+ on teh dyno but only runs a best of 10.78. Leaves hard out of the hole but then falls on its face on the big end. His IAT temps are too high and that is obviously pulling a crap load of timing out at mid track. He's upsized the H.E. relocated the IAT/MAF and even lowered the boost from 22 to 20psi and is now getting ready to add the meth injection to get the IAT's down. I can't remember what his IAT temps are but they are the source of his problem. He's also considering going to water cooled vice air-air.

He ever gets those IAT's down it will be flying. He's gota WOT N2MB on the setup (scares the crap out of you when he no loft shifts) with a T56 magnum 6 speed, full forged internals, cams, LT's, the whole ball of wax.

So upsizing the intercooler alone wasn't enough to bring the temps down? An air-to-water setup will definitely help. Seems like more power = more problems.

 

[stkjock]

The rev limiter is set to 6200 so that's where I shift. Maybe I'll get it raised and try again.

so u bang the limiter on every shift? you can't be shifting at 6200 if that's where the limiter is, you have to be shifting before it, from my experience, that typically means 200-300 RPM at least, or you're hitting the limiter.

A centri needs the RPM

 

[Marble]

It seems to me your car is pulling timing and may need some help with the tune. If it were me I would spin it a little more and do something about the IATs. Those are too high.

Other fixes can be getting a tune for race fuel only which you can run more timing with and is resistant to detonation and can therefore not pull timing with the higher IATs, but to me is not a real solution.

I think the fix is a really good tensioner, belt super tight, wastegate with a smaller pulley so boost level will be higher at lower rpms and not too high at the upper. And a good a/w heat exchanger.

 

[JeremyH]

Sounds like its pulling timing and killing power. Couple other thoughts is the cams. They might show a little more max power at max rpm from the higher lift but they are also a peak power na cam that ment to be rev'd. The frpp cams were designed with the frpp manifold and cnc head for good gains above 5k on an na setup where you rev higher, but with a power adder the excessive valve overlap from the tight lsa can "bleed boost" and hurt low to mid range. That mixed with your shifting at 6k rpms as you stated, you have a really narrow usable power band thats all up top. So the blower isn't doing much for you outside that over a modded na setup as you noticed. A mild boost centri setup likes rpm and gear to get things moving and in the power band, 373's and 6k max rpm is not enough for that setup to put up a good track time.

 

[46addict]

so u bang the limiter on every shift? you can't be shifting at 6200 if that's where the limiter is, you have to be shifting before it, from my experience, that typically means 200-300 RPM at least, or you're hitting the limiter.

A centri needs the RPM

I'm banging the limiter on the 1-2 shift, and you're right about deducting 200rpm to avoid hitting it. So probably 6k for the 2-3 shift. No need for 4th because the car is so slow lol.

It seems to me your car is pulling timing and may need some help with the tune. If it were me I would spin it a little more and do something about the IATs. Those are too high.

Other fixes can be getting a tune for race fuel only which you can run more timing with and is resistant to detonation and can therefore not pull timing with the higher IATs, but to me is not a real solution.

I think the fix is a really good tensioner, belt super tight, wastegate with a smaller pulley so boost level will be higher at lower rpms and not too high at the upper. And a good a/w heat exchanger.

Is there a way to tell if a tensioner needs replaced? I assume I'd be throwing belts if it's dead? Going by feel the blower belt seems tighter than the serpentine belt.

 

[redfirepearlgt]

So upsizing the intercooler alone wasn't enough to bring the temps down? An air-to-water setup will definitely help. Seems like more power = more problems.

It brought them down but not enough to satisfy Lund. I can find out what his IAT's have been since the upgrades. IAT's are fine on the dyno with a BF Fan blowing across the front end, but its in the track world where the IAT's rear their ugly heads at midtrack. If it will help I will contact him and get the 411 back to you. We're waiting for a dry Friday for some TT. Doesn't look like we will see one at this point until mid June it feels. Anothjer spring of dry Mon-Wed and April in May Thu - Sun.

 

[46addict]

No need to go out of your way. If he's running E85 his IAT threshold will be higher, among other variables different from my setup. But it would be nice to know what his before & after numbers were, out of curiosity. Has anyone tried running without the front bumper cover with their A2A intercooled setups?

 

[05stroker]

If you decide to do Meth, lmk, I have a nice setup for sale.

Also, IMHO, you need to spin to at least 6500 to get anything out of that blower. I would be spinning to 6800 myself, but to each is own.

 

[46addict]

Yeah with my pulley combo I'm turning just under 45k rpm, and it has 20k more left in it.

Revving another 500 engine rpm will net me 3700 blower rpm. I'm not sure if that will get me very far. It would be cool to have it act more like a PD blower.

So the to do list so far:
raise rev limiter
smaller pulley + wastegate
bigger IC or meth
sticky tires

Will a 75 wet shot cool the intake charge any? I assume it would do nothing for keeping timing up if sprayed after the MAF.

 

[RocketcarX]

If you decide to do Meth, lmk, I have a nice setup for sale.

Did the plug just show up?!

 

[JeremyH]

No need to go out of your way. If he's running E85 his IAT threshold will be higher, among other variables different from my setup. But it would be nice to know what his before & after numbers were, out of curiosity. Has anyone tried running without the front bumper cover with their A2A intercooled setups?

So removing the bumper would have very little to no measurable effect for a couple reasons. An A2A intercooler doesn't technically use convection to remove heat from the charge air, (its really air to solid to air) and it is still effective at cooling the air charge with little to no air passing through, unlike a water heat exchanger or radiator which performs poorly with no airflow through the core. Although airflow through an a2a of course helps, the aluminum intercooler heated up by the charge air will still readily radiate heat to the outside cooler ambient air regardless of forcing air through it from outside.

You could argue cooling could be worse with the bumper off as the intercooler would be in direct sunlight and you are making it easier for air to just splash around it. Much like removing the hood and the car running hotter. The grill and hood force incoming air to go through the radiator rather than take a path of least resistance around it etc.

A larger more efficient core volume, an additional cooler (water/meth) or a more efficient compressor or operating in a better efficiency range on the current compressor would be ways to lower final iat. A given compressor will have a sweet spot at a certain pressure ratio (boost level in relation to rpm, and volumetric efficiency of the motor) Meaning you could need more boost/rpm (or less) to put you in the most efficient island of the compressor, this will yield the lowest air temperature coming out of the compressor.

A trick I have seen at the race track to take advantage of latent heat of vaporization is spraying an a2a intercooler with a co2 extinguisher to rapidly cool it and form condensation or misting it down with ice water from a spray bottle. As the water droplets evaporate off the intercooler during a run it pulls more heat from the aluminum. Seen guys that swear by it. I imagine this concept is where intercooler co2 spray plates came from as well.

 

[JeremyH]

Yeah with my pulley combo I'm turning just under 45k rpm, and it has 20k more left in it.

Revving another 5k engine rpm will net me 3700 blower rpm. I'm not sure if that will get me very far. It would be cool to have it act more like a PD blower.

So the to do list so far:
raise rev limiter
smaller pulley + wastegate
bigger IC or meth
sticky tires

Will a 75 wet shot cool the intake charge any? I assume it would do nothing for keeping timing up if sprayed after the MAF.

That extra 500rpm is a big difference it widens your power band and puts you at a higher rpm in the next gear on an up shift keeping you in the optimal power band better.

 

[05stroker]

Did the plug just show up?!

What plug?

 

[05stroker]

That extra 500rpm is a big difference it widens your power band and puts you at a higher rpm in the next gear on an up shift keeping you in the optimal power band better.

Exactly, the rpms fall less and keeps the blower in a higher boost.

 

[46addict]

My tuner had me datalog and he has the timing at 20 degrees

Does anyone think this is too much for a car on 8-10psi running E10 93 octane?

I'm going to have my tuner bump the rev limiter but I'm afraid of breaking something. Should I have him reduce the timing a bit at the same time?

 

[05stroker]

Does anyone think this is too much for a car on 8-10psi running E10 93 octane?

I'm going to have my tuner bump the rev limiter but I'm afraid of breaking something. Should I have him reduce the timing a bit at the same time?

Not at 10psi. I used to run 18* on 93 with 16 psi. I run 23* with E85 and 21- 24 psi now without issue. 23* has always been my sweet see spot with C16 and E85. For pump I like to keep it below 18* but I run more boost then you. I would do what your tuner is comfortable with.