Roush 12psi vs Whipple 9psi

[imxz28]

Both being stage 1 kits, Does Roush really produce 12psi compared to Whipple 9psi.
And if so, is the Whipple at 9psi producing more at lower boost because of the cooler charge.

Apologies if this has been posted before.

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[Toydoctor]

Both being stage 1 kits, Does Roush really produce 12psi compared to Whipple 9psi.
And if so, is the Whipple at 9psi producing more at lower boost because of the cooler charge.

Apologies if this has been posted before.

From my personal experience with a roush 2018 phase one. With 12.5 psi I make more peak and midrange torque due to higher boost. Peak horse power on the roush is limited to supercharger inlet size and inefficiencies of lower manifold design.

The two kits seem on average seem to make the same peak power from various dyno graphs I’ve seen. Roush will make power earlier in power band.

 

[ugstang17]

The Whipple is a 3 Liter volume unit. The Roush a 2.65 Liter volume unit. Volume has to be factored in when comparing two different sized displacement units. At any given constant boost level the Whipple will move more air into the cylinder and do it under lower IAT (given identical heat removal systems). The Roush will need to run at a higher boost level to keep up with its 15% lower displacement size AND have a heat removal system capable of displacing that additional generated heat at the higher pressure level. (The higher the boost, the higher the air molecules are compressed...the more heat is induced in the pressurizing process).

The only disadvantage to the larger unit is the potential added weight on the front end vice the smaller unit. Had my 17 (second owner) not already had a Roush on it when I bought it, and at a very good price, I would have gone VMP or Whipple. They have much more efficient head units and many more options for heat removal over the Roush product. Roush offers no heat exchanger upgrades for their dinky little H.E. or any water pump upgrades. You have to source third party to make improvements in that area. Whipple and VMP both have several options. The VMP package for 18.19 comes with their highest end HE triple pass dual fan unit out of the gate. Whipple offers two HE upgrade options. The VMP though a 2.65L head unit will outflow the Roush with little effort even though they are the same displacement. Roush IMHO is for people are into designer label prestige. Whipple and VMP are work horses looking to get the job done.

So in the end it depends on what you are wanting to do. Are you wanting an SC for the purpose of being competitive or are you wanting something that just looks cool when you pop the hood at a car show and something with a little more fun for the drive there? If you are looking for the former, look to WHipple or VMP. If you are looking to the latter any of the three options will fit the application.

Personally if i were going to drop $9k today, I would look into a turbo setup...a good turbo setup like Hellion. I love the looks of a 'meat grinder' sitting in the valley of a V8 engine, but there is a lot to be said for a pair of twins being tucked under the hood these days...a LOT to be said. Def has me mulling a different direction for a future project.

Enjoy.

 

[Chainsaw]

The Whipple is a 3 Liter volume unit. The Roush a 2.65 Liter volume unit. Volume has to be factored in when comparing two different sized displacement units. At any given constant boost level the Whipple will move more air into the cylinder and do it under lower IAT (given identical heat removal systems). The Roush will need to run at a higher boost level to keep up with its 15% lower displacement size AND have a heat removal system capable of displacing that additional generated heat at the higher pressure level. (The higher the boost, the higher the air molecules are compressed...the more heat is induced in the pressurizing process).

The only disadvantage to the larger unit is the potential added weight on the front end vice the smaller unit. Had my 17 (second owner) not already had a Roush on it when I bought it, and at a very good price, I would have gone VMP or Whipple. They have much more efficient head units and many more options for heat removal over the Roush product. Roush offers no heat exchanger upgrades for their dinky little H.E. or any water pump upgrades. You have to source third party to make improvements in that area. Whipple and VMP both have several options. The VMP package for 18.19 comes with their highest end HE triple pass dual fan unit out of the gate. Whipple offers two HE upgrade options. The VMP though a 2.65L head unit will outflow the Roush with little effort even though they are the same displacement. Roush IMHO is for people are into designer label prestige. Whipple and VMP are work horses looking to get the job done.

So in the end it depends on what you are wanting to do. Are you wanting an SC for the purpose of being competitive or are you wanting something that just looks cool when you pop the hood at a car show and something with a little more fun for the drive there? If you are looking for the former, look to WHipple or VMP. If you are looking to the latter any of the three options will fit the application.

Personally if i were going to drop $9k today, I would look into a turbo setup...a good turbo setup like Hellion. I love the looks of a 'meat grinder' sitting in the valley of a V8 engine, but there is a lot to be said for a pair of twins being tucked under the hood these days...a LOT to be said. Def has me mulling a different direction for a future project.

Enjoy.

Wrong. Roush now has an upgraded H.E. along with a new calibration.

 

[Beano]

The Whipple is a 3 Liter volume unit. The Roush a 2.65 Liter volume unit. Volume has to be factored in when comparing two different sized displacement units. At any given constant boost level the Whipple will move more air into the cylinder and do it under lower IAT (given identical heat removal systems). The Roush will need to run at a higher boost level to keep up with its 15% lower displacement size AND have a heat removal system capable of displacing that additional generated heat at the higher pressure level. (The higher the boost, the higher the air molecules are compressed...the more heat is induced in the pressurizing process).

*snip.

It doesn’t make sense.....the downstream cylinder volume/stroke/rpm (thus displacement) would determine the volume consumed....I know why you would think that, but 15psi boost from a 2.65l volume SC = 15psi boost from a 4.6l SC......(of course ignoring lower temp/higher density charge from the larger volume blower....)

I fully agree that at the same pressure, a larger blower can move a bigger volume of air....which might be required for a bigger displacement engine, but I suspect it is a non-issue for the hp levels we are talking about in a high CR supercharged 5.0l Coyote engine....other then dedicated racing engines, I doubt we can flow enough to bring a 2.65l TVS to its knees.....Thus it should be able to flow enough to sustain possibly 20-25psi in our given application....

But I totally stand to be corrected/educated...

Cheers,
Beano

 

[ugstang17]

It doesn’t make sense.....the downstream cylinder volume/stroke/rpm (thus displacement) would determine the volume consumed....I know why you would think that, but 15psi boost from a 2.65l volume SC = 15psi boost from a 4.6l SC......(of course ignoring lower temp/higher density charge from the larger volume blower....)

I fully agree that at the same pressure, a larger blower can move a bigger volume of air....which might be required for a bigger displacement engine, but I suspect it is a non-issue for the hp levels we are talking about in a high CR supercharged 5.0l Coyote engine....other then dedicated racing engines, I doubt we can flow enough to bring a 2.65l TVS to its knees.....Thus it should be able to flow enough to sustain possibly 20-25psi in our given application....

But I totally stand to be corrected/educated...

Cheers,
Beano

The higher efficiency displacement allow for lower molecular temps which result in higher volumetric fill. So yes we agree. Its like trying to fill a jar with marbles vice filling the jar with sand (equating a grain of sand and a marble as the air molecule represented at two different temps). While my theory was not including the factor of filling a fixed displacement engine the end result is still more air in the combustion chamber. Thank you for helping me see that.

VMP will only tune their 2650 unit package with no smaller than an 88mm pulley for 93 on a 15-17GT. Below that requires boostane or E-85. With the 2300 unit (Roush will go 76 and VMP 79 as I recall because the VMP flows better) they have told me that I could go as low as a 79 or 76mm pulley and still be good on 93, even runningn a twin 67mm TB. Of course this is with properly accommodating fuel injectors and fuel system to support the 79 or 76mm pulley on the 2300 TVS. So all science aside and just looking at the pulley spec differences between the two on the same given application, there is clearly more air movement but obviously due to lower molecular temps as mentioned above.

 

[ugstang17]

Wrong. Roush now has an upgraded H.E. along with a new calibration.

So they do. It's still a whimpy single pass unit (whimpy regardless of being upgraded) that pails in comparison to the two upgrade options offered by Whipple and the standard triple pass H.E. offered by VMP.

As for their "calibration".........it is better than a Bama tune. I will give them that. The Roush cal is for little old ladies and people overly paranoid about voiding a warranty.

 

[Beano]

Hi, again you talk about higher efficiency - in the case you referenced earlier, Whipple vs the TVS. I already acknowledged that (the same design) bigger blower will have lower charge-air temp, thus higher densities, thus at the same boost-level, should be able to cram more molecules into the engine.

But I am questioning if the 3l Whipple indeed has a higher adiabatic efficiency than the 2.65l TVS, because there are significant design differences in the lobes. Your argument is based on the premise that it indeed is the case, I am not so sure. Anyone that knows the facts in this case?

 

[Toydoctor]

VMP just posted a video about supercharger displacement comparison. This is an extreme example, but still at the same boost levels.

 

[Beano]

^^ For the record: I have a Roush 670hp setup in my car from the factory, but during the BF sales, I ordered a Gen3R VMP head unit, twin 69mm TB and the Whipple oversized HE....I will get a few more parts locally to effect the swap, including a few bits and pieces from MFP here in Australia.

‘With that said, the performance of the Gen3R in that video is very commendable, when compared to the much larger KB....but it probably doesn’t highlight the fact that the larger blower made a higher torque than the VMP. Upper-rpm range hp is good for high trap-speeds, or perhaps high-speed circuit-racing, but for drags, the average power-curve will play a significant role in lowering ET’s....

‘Provided you can get the ideal hook-up off the line, I dare say the larger KB will provide a fraction quicker ET’s than the VMP. It is possibly providing cooler charge-temps, thus higher density, explaining the torque-differential....the ave torque on that larger blower is very impressive, to say the least, a much wider curve than the Gen3R....but again, fully expected.

I wish VMP, and SC Suppliers in general, will share the overlay graphs, which will highlight a few key differences....plus, ideally, it would be good to know the adiabatic efficiencies of the different blowers available today....but instead they sad,y only talk about peak hp numbers :(

Cheers,
Beano

 

[Avispa]

Toydoctor, you're right down the road from me.

 

[ugstang17]

Hi, again you talk about higher efficiency - in the case you referenced earlier, Whipple vs the TVS. I already acknowledged that (the same design) bigger blower will have lower charge-air temp, thus higher densities, thus at the same boost-level, should be able to cram more molecules into the engine.

But I am questioning if the 3l Whipple indeed has a higher adiabatic efficiency than the 2.65l TVS, because there are significant design differences in the lobes. Your argument is based on the premise that it indeed is the case, I am not so sure. Anyone that knows the facts in this case?

PM sent.

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