3.4 vs 4.0 Whipple


REDEEMED

GT Owner
Mark II Lifetime
Oct 10, 2008
142
So who has driven the 3.4 and then gone to the 4.0 Whipple?

How much torque gain down low? Is the gain well worth it? Pros and cons---please elaborate.

Many thanks, REDEEMED
 

Lorenzo

GT Owner
Mark II Lifetime
Dec 28, 2008
626
U.S.A.
If you trying to choose from one or the other you might want to check with Whipple on the availability. When i bought mine last year they only had one left and i was told at that time that there will be no more of the 3.4 version.

Now having said that, one thing i have learned over the years is that you should never say never, and im sure if you want a 3.4 version that one could be obtained some way or another.
Although i can not answer your question i can say that the 3.4 made a huge differance in the overall driving experience of the car thanks to Shadowman :cheers
 
Last edited:
Aug 25, 2006
4,436
Thank you Lorenzo

FYI I installed a 3.4 a year ago for him and now is considering the 4.0 as an upgrade while she is under the proverbile knife for other personal touch items

Takes care

Shadowman
 

lthlvpr

GT Owner
Mar 8, 2006
299
Does anyone know what the exact differences are between the Gen I 3.4L kit for the GT and the Gen II kit? Not sure if there was a Gen III 3.4L or if it was just the 4.0L that became the GEN III.
Anyone know?
 

Black GT

GT Owner
Mark II Lifetime
Jan 2, 2006
771
No one seems to have an answer. Looks like in some other 4l threads i have seen. It looks like 30 or 40 rwhp. But, I can't get real info. Would like some numbers on the 4l.
 

Fubar

Totally ****** Up
Mark II Lifetime
Le Mans 2010 Supporter
Aug 2, 2006
3,979
Dallas, TX
go with the 4.0L... it's got more liters.
 
Aug 25, 2006
4,436
Does anyone know what the exact differences are between the Gen I 3.4L kit for the GT and the Gen II kit? Not sure if there was a Gen III 3.4L or if it was just the 4.0L that became the GEN III.
Anyone know?

Exactly ... no however the physical size is the same for Gen I and Gen II however the Gen II had a few internal changes; vented snout rather than sealed gear case, new rotor design, and ??? It was touted as more efficient when compared the Gen I however IMO the Gen I is a great unit and the Gen II was more hype and an internal means for Whipple to reduce part numbers; as I recall there were changes to the Gen II specifically for off shore activities that would not hurt the road going gals as such a solo part number was born.

Now as for the Gen III; as Fubar states; it is larger in displacement and IMO has the ability to do more when compared the Gen I and Gen II however IMO to get the maximum benefit of the greater supercharger displacement several tweaks such as fueling needs to be tended to otherwise it presents results comparable to the Gen I and Gen II.

Having said this; all three supercharger versions are very nice and IMO the results with a modest 01 octane tune and only creating 19 psi when compared to OEM are nothing short of staggering.

Takes care

Shadowman
 

GTFUN

GT Owner
Aug 19, 2009
271
Atlanta,Ga
I could not tell you the difference from the 3.4 gen II or 4.0...

I just installed a lightly used 3.4 and the car went from 600 RWHP with a pulley and tune to 711 RWHP tuned conservatively...

BIG difference for me and I'm done with power upgrades :)

Install &Tune done by Kurgan Motorsports:

Here are the pics and dyno sheet before and after:
http://www.kurganmotorsports.com/site/customer-cars/customer-cars/ford-gt-whipple-3-4
 
Last edited:

GTED

GT Owner
Apr 4, 2006
783
As for data you requested, at the 50k mile thread, someone stated having 770rwhp with a 4.0ltr Whipple. I recently had a new GenII installed and dyno'd it at 726rwhp, while right before the install we did a baseline dyno at 621rwhp on the, then, existing set up of pulley&tune. I've been told that my before/after rwhp readings are very typical from such mod. As it's been said many times by others, I was perfectly happy with the pulley & tune, now I have a slightly bigger smile with the Whipple... Only if there are so many LEOs on the road here in CA.
I opted for the GenII because I didn't want deal with the potential fuel upgrade requirement.

Ed
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,337
GTED

You experiences are exactly in line with our results as also with the numerous dyno sessions that we have hosted. The basics are that the pulley and tune will yield approx a 100 RWHP increase. Clearly this is one helluva bang for the buck. The next 100RWHP is considerably more expensive - but adds the pleasures of a very predictable, linear power curve. This is what you have and love with the 3.4. Similar results can be had with the 4.0L Whipple with modest (19 psi) boost levels. The 4.0L also provides the opportunity to be tuned to a higher PSI output and depending on how far you go, more fuel may be needed. The fuel mods necessary can vary from mild to wild.

Be careful of the shops that have snowed their customer to believe they have 800 or more RWHP on a 3.4 Whipple with 19-20psi. These are exaggerations and where there is subjective testing - dyno back to back with similar cars and/or standing mile results, the outcomes don't lie. Don't believe everything you hear.
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
Be careful of the shops that have snowed their customer to believe they have 800 or more RWHP on a 3.4 Whipple with 19-20psi. These are exaggerations and where there is subjective testing - dyno back to back with similar cars and/or standing mile results, the outcomes don't lie. Don't believe everything you hear.

I have never heard of or read of any shop claiming 800 RWHP with a Gen 1 or 2 Whipple with only 19 or 20 PSI, but if there was someone claiming that I would agree that the claim is an exaggeration, or the dyno is very wrong. A fellow forum member told me that the tungsten FGT that Tanner Foust ran at the TX mile dynoed more than 800, but that is the only one I know of. I believe it was running more than 20 PSI with water/meth injection with a Gen2.

IMO you cannot safely get to 800 RWHP with the stock fuel system with a blower. Have to have a BAP and/or supplemental fueling via water/meth injection. Larger injectors would be nice too.

Using the stock injectors with the stock delta fuel rail pressure of 39 PSI the injector duty cycle is max out! I was getting more than 90% duty cycle on both the fuel pumps and injectors at the last Mojave event running a 21 PSI pulley on a gen 1 and that was at 2700'. Based on the MAF count logged that was less than 730 RWHP during that event. On a good day at sea level it would surely run lean.
 
Last edited:

B.M.F.

GT Owner
Mark II Lifetime
Jan 29, 2009
1,834
Minnesota
The Tungston Tanner Foust car just shipped to China..... I took some pics of it and the intake kit before it got loaded on the trailer. Pretty cool car, Had a nice alum intake kit with out factory air box.
 

GTED

GT Owner
Apr 4, 2006
783
I think when Tanner quoted 800 he meant 800bhp and NOT rwhp because of tv audience is more acustomed to the bhp measurement from reading car mags.

Kendell, thx for confirming my data.

Ed
 

soroush

Ford Gt Owner
Mark II Lifetime
Aug 8, 2007
5,256
the tungsten car actually made 850 hp to the wheels, I have seen the dyno numbers. the car had stainless exhuast, 3.4 whipple, 23lb pulley, race gas and meth injection, 24 deg timing it made a little over 850 to the wheels.
 

2112

Blue/white 06'
Mark II Lifetime
The Tungston Tanner Foust car just shipped to China..... I took some pics of it and the intake kit before it got loaded on the trailer. Pretty cool car, Had a nice alum intake kit with out factory air box.

And you are going to share them pics with us, right? :biggrin
 

JAYGT

GT Owner
Nov 20, 2010
175
MIAMI
BMF pics or ban!:ban:
 

Black GT

GT Owner
Mark II Lifetime
Jan 2, 2006
771
766.6rwhp with a Gen @ 3.4L. Love the power.
 

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,112
St Augustine, Florida
I remote calibrated a stock 4.0L Whipple GT the other day in Germany :
 

Attachments

  • Untitled.jpg
    Untitled.jpg
    101.1 KB · Views: 682

911teo

GT Owner
Mark IV Lifetime
Jan 5, 2007
628
Surrey, UK
Having driven both the 4.0L and the 3.4L Gen II extensively I can say that, leaving ALL fueling issues aside (the cars were set up very conservatively in both situations):

- The 3.4L is enough to fill that lack of acceleration and push you feel when flooring over 100mph
- In reality the 3.4L is all you need
- The 4.0L is in a different league and scared the crap out of me every time I was a little aggressive on the throttle
- The perceived torque difference between the 2 is noticeable, especially between 3k and 5k
- With the 4.0L the Ford GT is mental, with the 3.4L is a very quick car

But

I was treating my throttle as if I had egg-shells under it with the 4.0L whilst I was a bit more liberal with the 3.4L.
 

GTFUN

GT Owner
Aug 19, 2009
271
Atlanta,Ga
The 3.4L is enough to fill that lack of acceleration and push you feel when flooring over 100mph
- In reality the 3.4L is all you need

A supercharger is tough on a motor... I went with the 3.4 because it is ENOUGH for me and is easier on the motor..

I believe it will preserve the life of engine by having the 3.4 and tuning it conservatively.

I know some guys want more power than that, but I think the most I would do in the future is change the pulley to gain some more HP but don't think I'll do that for a while..