Finally hit the dyno!

[o2sys]

Looking at the dyno sheet and the curve the peak power isn't reached until 5-6k rpm. Is this how it's supposed to be with a centri? Feels like VTECH, short burst of power for a split second before I shift again lol.

I want to reach peak psi sooner without increasing boost. Like I said before running 93 with 10.5cr is limiting this.

 

[Wild White Pony]

Looking at the dyno sheet and the curve the peak power isn't reached until 5-6k rpm. Is this how it's supposed to be with a centri? Feels like VTECH, short burst of power for a split second before I shift again lol.

I want to reach peak psi sooner without increasing boost. Like I said before running 93 with 10.5cr is limiting this.

IMO don't start looking for new setup changes yet till your tuner gets a chance to change look at datalogs and make some changes.

This is a Centri setup, the CR I wouldn't get to hung up on as the limiting factor here. Centri's build boost and have a very linear curve like the one you have. If you had that CR and a direct displacement or turbo, I would be concerned with tip in detonation from IAT temps,timing and boost. Your graph curve looks low in power period, it starts to flatten around 6k, normally where it should be really producing all the way to at least 6800rpm even on stock springs and cams and they got out of it by 6500rpms?

I just think before you start bringing in the power band sooner it would be better to work out this current package. Must be a lot of peeps here who have that paxton with much larger hp graphs they could post up for comparison along with some parameter data they recorded.

Later you can add meth or E85,wastegate, O.D. Crank, Smaller Pulley to bring in the power sooner and bigger. Adding boost sooner but not increasing total boost is not going to work without a wastegate. If your just worried about Detonation throw the meth on to raise the octane or convert to E85. The E85 route removes the mechanical fail out of the equation but it seems lately that the gas stations are reducing content to E75 more and more, could be harder to find good E85 fuel in the future

 

[BruceH]

OKAY OP. So you're saying that at 12psi+ after the HE on the boost side you're measuring "near ambient temps" on IAT with this setup? At WOT? Across the entire power curve? That is pretty amazing of the Paxton package. How does the dyno IAT compare to the real world of making a pass ? If the H.E. and centri are that efficient you should be able to run 20 degrees of timing or even more with octane being the only limiting factor. IMO based on that, your next upgrade would be more boost, and more aggressive tune. But I'd make a hit with it at the track first to see what it will do and datalog it. That would give the tuner better data to get more aggressive on the tune without going stupid far. Almost has me thinking about selling the whole TVS setup and going to a PAXTON on the ole KY-YO-TAY.

10psi with a centri doesn't generate a whole lot of heat that the air to air intercooler can't take care of. When I had a Paxton 1200 set up as a blow through at 10psi my iats were close to ambient at wot all the way to redline.

The hitch is that the iats were taken right before the air went into the intake. Most pd blowers will have the iat sensor in a runner just before the air enters the combustion chamber so it's not apples to apples.

I've also run a D1 Procharger and the iats from it were warmer than the Paxton but it was pushing 19psi. There is a huge difference in what it takes to generate 19psi vs 10psi and the subsequent heat generated.

As for the question about how does the dyno compare to making a real world pass the pass will always have lower iats because more air is passing though the air to air intercooler. There is a point where air to water will cool more than air to air with a centri but it's out of the street car realm.

 

[redfirepearlgt]

10psi with a centri doesn't generate a whole lot of heat that the air to air intercooler can't take care of. When I had a Paxton 1200 set up as a blow through at 10psi my iats were close to ambient at wot all the way to redline.

The hitch is that the iats were taken right before the air went into the intake. Most pd blowers will have the iat sensor in a runner just before the air enters the combustion chamber so it's not apples to apples.

I've also run a D1 Procharger and the iats from it were warmer than the Paxton but it was pushing 19psi. There is a huge difference in what it takes to generate 19psi vs 10psi and the subsequent heat generated.

As for the question about how does the dyno compare to making a real world pass the pass will always have lower iats because more air is passing though the air to air intercooler. There is a point where air to water will cool more than air to air with a centri but it's out of the street car realm.

Good info. Thanks. I knew where the IAT2 sensor is on the PD, thought there were two on the centri as well. Makes sense why there is not. Also explains the higher HP output (lowerT value though) given similar boost levels when compared. Do they make a centri setup that doesn't blow off like a Subaru ricer tuner every time you let off the gas? Would be nice to purchase a Blow off, bypass or whatever valve you wish to call it on a centri setup that doesn't sound that way and doesn't alert the media you are running FI. Some of us enjoy shocking the crap out of someone unsuspecting. Especially when they roll upon me, seeing my gray hair, and want to play because they slipped daddy's corvette out for a joy ride. LOL!

 

[95ragtop]

Not sure on Coyote setups but I know on the 3V vortech and paxton setups they run the bypass valve back to the intake so it doesn't vent to atmosphere, which keeps it quiet. I have heard the 1" bypass valves are a restriction around 10psi, so to keep it quiet in a vent to atmosphere setup guys have run an air filter on it.

 

[redfirepearlgt]

Not sure on Coyote setups but I know on the 3V vortech and paxton setups they run the bypass valve back to the intake so it doesn't vent to atmosphere, which keeps it quiet. I have heard the 1" bypass valves are a restriction around 10psi, so to keep it quiet in a vent to atmosphere setup guys have run an air filter on it.

BERRRY EEEENTERESTINNNNNNGG. Thanks.

 

[01yellerCobra]

BERRRY EEEENTERESTINNNNNNGG. Thanks.

It all depends on the bypass set up. I ran a Vortech Mini Race and it wasn't too bad. My Tial 50mm on the other hand wasn't so quiet. It didn't sound like a Subaru though.

What intercooler is your buddy running? Even with my F1A at 19psi I was never that much above ambient. I remember being surprised when I saw 106 degree. Then I saw ambient was in the mid 90's.

 

[o2sys]

IMO don't start looking for new setup changes yet till your tuner gets a chance to change look at datalogs and make some changes.

This is a Centri setup, the CR I wouldn't get to hung up on as the limiting factor here. Centri's build boost and have a very linear curve like the one you have. If you had that CR and a direct displacement or turbo, I would be concerned with tip in detonation from IAT temps,timing and boost. Your graph curve looks low in power period, it starts to flatten around 6k, normally where it should be really producing all the way to at least 6800rpm even on stock springs and cams and they got out of it by 6500rpms?

I just think before you start bringing in the power band sooner it would be better to work out this current package. Must be a lot of peeps here who have that paxton with much larger hp graphs they could post up for comparison along with some parameter data they recorded.

Later you can add meth or E85,wastegate, O.D. Crank, Smaller Pulley to bring in the power sooner and bigger. Adding boost sooner but not increasing total boost is not going to work without a wastegate. If your just worried about Detonation throw the meth on to raise the octane or convert to E85. The E85 route removes the mechanical fail out of the equation but it seems lately that the gas stations are reducing content to E75 more and more, could be harder to find good E85 fuel in the future

I wasn't sure so I told them to just go up to 64-6500rpm. No E85 available for me which would solve a lot of my concerns.

Still can't understand the concept of a WG on this setup.

 

[redfirepearlgt]

It all depends on the bypass set up. I ran a Vortech Mini Race and it wasn't too bad. My Tial 50mm on the other hand wasn't so quiet. It didn't sound like a Subaru though.

What intercooler is your buddy running? Even with my F1A at 19psi I was never that much above ambient. I remember being surprised when I saw 106 degree. Then I saw ambient was in the mid 90's.

Did your inlet route like a classic Procharger that sucks air up past the headers? THat's how his is setup and somethign I have always questioned with regard to design.
The intercooler is a monster air to air he built himself with a core he obtained on line, to teh same specs as one of the well known models. It's gi-normous. He had to cut the crap out of the bumper cover to get it all to fit. And yes he is running an F1A. Lund is tuning the car. IAT's are spiking at the track just past the 1/8th even in cool spring air and pulling timing to the point that he is running 3-5 degrees by that point. As I recall they were above 160 after all of the changes to bring them down. He says its like he hits a wall just past the 1/8th. And the timing and IAt's on the log reflect that directly. Relocation of the IAT sensor has been tried thinking it wasn't measuring temps right. No help. He's spent thousands and runs about a 1/10th faster best than I have.

He will likely make some passes this coming weekend if the weather holds and the track is still open. He lost the clutch three months back and has been breaking in his new McLeod dual disc setup.

 

[01yellerCobra]

Did your inlet route like a classic Procharger that sucks air up past the headers? THat's how his is setup and somethign I have always questioned with regard to design.
The intercooler is a monster air to air he built himself with a core he obtained on line, to teh same specs as one of the well known models. It's gi-normous. He had to cut the crap out of the bumper cover to get it all to fit. And yes he is running an F1A. Lund is tuning the car. IAT's are spiking at the track just past the 1/8th even in cool spring air and pulling timing to the point that he is running 3-5 degrees by that point. As I recall they were above 160 after all of the changes to bring them down. He says its like he hits a wall just past the 1/8th. And the timing and IAt's on the log reflect that directly. Relocation of the IAT sensor has been tried thinking it wasn't measuring temps right. No help. He's spent thousands and runs about a 1/10th faster best than I have.

He will likely make some passes this coming weekend if the weather holds and the track is still open. He lost the clutch three months back and has been breaking in his new McLeod dual disc setup.

This was on an 01 Cobra. With the F1A I was drawing air from the fender well. I did have a Vortech T trim that was pulling air straight from the radiator. I was just running a screen. It was only at 15psi though. Both blowers were used with the same Procharger 3 core intercooler though.

He might have to do some fencing to direct air. Otherwise I'd be concerned about air flow through the intercooler itself.

 

[redfirepearlgt]

^^^ Thanks. Will advise.

 

[46addict]

Whatever its called on the centri. Funny, a friend has a prochrager setup and heat soaks the crap out of it. Has up graded the IC and still can't keep IAT's beklow 170 @ mid track in good air. Running 19-20psi on E-85cmaking over 700RWHP on a forged 3V .020" over. Nice setup, pretty to look at, makes nice dyno numbers, but only a 1/10th or so quicker than mine down the track with 150+ more HP dyno sheet per dyno sheet (same dyno btw). Thats my exposure to centris and IAT comparisons. Was enough to turn me off. May have to look into a centri setup if they make one that doesn't sound like a Subaru exhaling every time you let off the throttle.

No issues with my triple pass VMP heat soaking. 130 tops in 90 degree air.

Centri set ups are cool if you get them working right. I'm not sure why his IATs are so high but Billy, who is on this forum (05stroker), has an F1A setup on E85 running 22+ psi of boost. Stroked and bored 3v engine if I'm remembering right. Don't know the dyno numbers but it's good enough to run low 9s with full interior. Very respectable car and it's one of my favorite cars on this forum. You friend could probably get some pointers from him.

 

[46addict]

Question for the dyno gurus..Is it typical for dyno operators to apply a standard correction factor for pulls instead of the SAE factor? From what I understand, the latter is a more realistic correction (at least for southern states) due to the barometric pressure and air temp used in the calculation. An uncorrected number could have yielded higher numbers if ambient temp was less than 60F on a sunny day.

 

[redfirepearlgt]

Centri set ups are cool if you get them working right. I'm not sure why his IATs are so high but Billy, who is on this forum (05stroker), has an F1A setup on E85 running 22+ psi of boost. Stroked and bored 3v engine if I'm remembering right. Don't know the dyno numbers but it's good enough to run low 9s with full interior. Very respectable car and it's one of my favorite cars on this forum. You friend could probably get some pointers from him.

Thanks. I'll look him up. Maybe he can give some advise I can pass on. The guy I am referring to isn't on this site. He doesn't do forums very much if any.

 

[46addict]

Thanks. I'll look him up. Maybe he can give some advise I can pass on. The guy I am referring to isn't on this site. He doesn't do forums very much if any.

Here is the build thread if you're interested. http://www.s197forum.com/forum/showthread.php?t=88353
There are over 2500 posts in here so be forewarned, but if you're into build threads this one is quite inspiring.

Sorry OP for totally derailing the thread.

 

[Department Of Boost]

Paxton uses an air to air intercooler not a heat exchanger. They are more efficient than water cooled intercooler and don't heat soak so easily.

That is 100% false.

 

[o2sys]

That is 100% false.

100% true in my experience.

 

[Department Of Boost]

100% true in my experience.

Science says otherwise.

For a given surface area water transfers heat faster than air. A lot faster. Comparing an incorrectly sized A2W to a correctly sized A2A will not provide the data needed to compare the two methods.

Additinally when comparing the two systems on a Mustang for example your IAT data is taken at two completely different points in the system with two completely different senosr behaviors. They can only be compared anecdotally.

 

[BruceH]

Science says otherwise.

For a given surface area water transfers heat faster than air. A lot faster. Comparing an incorrectly sized A2W to a correctly sized A2A will not provide the data needed to compare the two methods.

Additinally when comparing the two systems on a Mustang for example your IAT data is taken at two completely different points in the system with two completely different senosr behaviors. They can only be compared anecdotally.

All true. However, the amount of air flowing over an air to air intercooler at cruising speed is significantly more volume than the amount of water flowing through the intercooler and heat exchanger on an air to water system.

In a way the two systems are opposites in how the supercharged air is cooled.

Air to air routes the intake air through the intercooler where the heat is dissipated through the fins to the air flowing past them.

Air to water pushes intake air past the intercooler fins, heat is absorbed into the water flowing through the intercooler and the water is pumped to a heat exchanger where air passing over the fins cools the water.

 

[TheKurgan]

It's a simple thing to prove. Just datalog the two. I always see around ambient with my turbonetics A2A. On the blow off valve subaru sound we're not really trying to sound like a suburu either, just make the most effective horsepower possible.