17 psi

[palehorse]

I am trying to limit this poll so that I get opinions as to efficency and maintaining torque at low rpm levels.

So for purposes of this poll do not consider price, necessary modifications, supporting mods, "expandability" or brand loyalty or reputation.

I just want opinions on what blower will make the most hp at 17 psi, and not lose any low end torque.

 

[Tom's_03SVT]

if the Whipple 3.4L doesnt than theres a big problem, that is a huge displacement blower.

Tom

 

[Venomous01]

Pointless to run a big displacement blower at that psi.

Those big displacement blowers need to be run at higher psi on a fully built motor.

 

[lloyyd]

Pointless to run a big displacement blower at that psi.

Those big displacement blowers need to be run at higher psi on a fully built motor.

That's what I thought too. FWIW, I'm on 17psi & made 625/569, though I would think that any twin screw is gonna make lots of torque down low.

 

[snake134]

has anyone installed the 3.4 yet? :shrug:, i know its not out yet, but you guys with the "connections"

 

[04MystiCobra]

I think even the Whipples guy said if you're running at low boost levels that the 2.3 was better suited.
If you take a look at the GT500 w/ the 2.8 you'll see it makes a minimum of 600+rwtq from 2000rpm all the way to redline! I'm sure the Whipple will do the same but if you're looking for most tq at, low rpm on 17psi you may be able to save some funds and go for the 2.4L KB or the 2.3L Whipple.

 

[wheelhopper]

You might as well pull the H series blowers from the list. They are designed to run best w/over 19lbs.

 

[DSG03Cobra]

You might as well pull the H series blowers from the list. They are designed to run best w/over 19lbs.

He's only looking for info on 17psi, so the H series wouldn't be as beneficial at that psi.

I've got the Whipple 2.3 and put down 572rwtq w/ the tune still a bit rich. I had 500+rwtq at 2300 rpm's and hit 550rwtq by about 3500 rpm's. Also had 582rwhp with 20* timing. Pretty sure when the tune gets cleaned up 600rwhp and 590rwtq shouldn't be too far off.

I think it's the perfect combo for a street machine w/ the occasional trip to the strip. :banana:

 

[Screamin Cobra]

2.6 Kenne Bell for sure, also for lower IAT temps at this boost level.

 

[Sonic03inSC]

Whipple @ 17psi stock lower 3.0 upper & stock manifolds with 5k miles on the CF LM clutch.
Blew the tires off on the first run. I'll also be tweaking the tune little.

 

[palehorse]

I have heard that the big displacement blowers actually "build" boost like a centrifugal throughout the lower rpm range, although not anywhere near that significant or pronounced. I guess I should have also added as a possible answer that some of them would be equal in terms of torque and hp at that level.

 

[OrangeRocket]

I heard the new Whipple will only spin to 14k rpm, where the 2.8L KB will spin to 18k rpm. Anyone have a confirmation there?

 

[Black2003Cobra]

I heard the new Whipple will only spin to 14k rpm, where the 2.8L KB will spin to 18k rpm. Anyone have a confirmation there?

If you mean the new W210AX, its max speed is 18 krpm. Max boost is 35 psi (30 psi continuous).

 

[HISSMAN]

Whipple @ 17psi stock lower 3.0 upper & stock manifolds with 5k miles on the CF LM clutch.
Blew the tires off on the first run. I'll also be tweaking the tune little.

Focus on tuning the the low end of the RPM. That is where I spent most of my time when I was building my most recent tune. As soon as I stomp on the go pedal my torque jumps to about 555 at just 3200 rpm and builds from there. Of course I have a 26 spline DFX clutch that could be helping me out a little bit too.

-Jeff

 

[palehorse]

Your set up is exactly what I would like to be running. Stock Lower 3 inch upper. Is this tune on 93 octane?


So My question to you is do you think with your exact set up with the 3.4 set to 17 PSI you would see any significant gain due to less parasidic loss or lower IAT temps?

Stated another way, if you are at 605 HP with the 2.3 would you expect to see even 620+ on your exact set up only swaping to the 3.4?

I'm not suggesting it is worth it, and I am not talking out the potential at higher boost or built engine. I'm talking straight swap. I know no one knows for sure yet, but please speculate!

 

[HISSMAN]

Same setup with a 3.4 and some minor tuning adjustments for the different blower should get you to about 650+ rwhp with no problems.

-Jeff

 

[Black2003Cobra]

Palehorse – Your last sentence says it all. Since no one has the compressor maps, no one can give you an answer. I'm sure the new 3.4L is a great SC, and no offense to the previous poster, but to see an increase of >45 rwHP (650-605) would mean an increase of more than 45/0.85 ≈ 53 hp at the crank. And a reduction of SC drive power that large would require an unrealistic increase in adiabatic efficiency, AE. So don't expect that large a gain.

From the available maps, what we do know is that the old 2.3L Whipple has a total AE of around 56% at around 17 psi and the commensurate flow rate. (AE is a function of pressure ratio and blower speed or flow rate). This translates to an estimated drive power of around 118 fwHP (crank HP) for those conditions. So even if the new blower’s adiabatic efficiency were 100% at that boost pressure and flow rate, (which it absolutely can not be), that would mean the SC drive power would drop to 118*0.56 = 66 fwHP. Hence, that translates to a gain of (118-66) = 52 fwHP or 0.85*52 = 44 rwHP. But since a total AE of 100% is impossible, (unless someone can figure out a way to break the second law of thermodynamics), that won’t happen. So again, no offense, but a gain of >45 rwHP just isn’t going to happen.

If you want a guess, I don’t think the total AE could/would be much higher than 60-65%, or so. At the same conditions (boost and flow rate), a total AE of ~65% would translate to a SC drive power of around 66/0.65 = 101 fwHP, which only means a gain of 0.85(118-101)=14 rwHP. Heck, even an AE of 70% would only translate to a gain of ~20 rwHP, (and an AE of 70-75% is centri territory!) So don’t expect to see that big a difference with just a blower swap at the same boost pressure and with the same tune, etc.

 

[palehorse]

Thanks. That is just the kind of "speculation" I was hoping someone smarter then me could post up. So if the AE on the new blower can't be high enought to increase more then 15-20 hp at same boost level, what about cooler intake temps. How drastic would the decrease in the IAT temps have to be (at same boost level) to equate to significant power increase (meaning closer to mean best timing in tune). And is it realistic to add the to "guestimated" 15-20 hp gained as a result of greator AE to the "guestimated" power increase resulting from lower IAT temps?