12-07-2004, 01:29 AM
Just picked up an SVTF with a JRSC. On all of my other cars a 65MM TB is a must. I just called Jackson Racing and they said they dont recommend 65MM with the blower since they said they lost some midrange.
However, I understood their TB werent that good and they are not on the market anymore.
Looking specifically for owners with JRSC who have put a larger TB to see what they thought.
Its a nice improvement on NA cars and would like to see if it performed better on a FI SVTF.
Please, no supposition. Just guys with experience.
12-07-2004, 01:48 PM
Originally posted by fstrdnu
I understood their TB werent that good and they are not on the market anymore.
Precision: I have their TB and it's as good as the FC TB. Same thing except it's only for 5spd tranny.
Good luck with your SuperCharger.
12-07-2004, 07:31 PM
Nobody has put a 65MM TB on a JRSC?
I cant beleive Im going to be the first.
12-07-2004, 07:58 PM
You should tell us if you see any difference with the 65 mm TB on and off
12-07-2004, 09:45 PM
Without input Im not gonna spend the $270 plus $200 for dyno time to possibley get 5-7hp. Looking for someone who has already done it and could tell me, and backup with dyno sheets, that this mod is worth the cost.
12-07-2004, 09:48 PM
well i would believe JR, since they have done their testing and dyno'ing. If they say that it will not be beneficial, then i'd take their word. But did they say anything about loosing midrange, but gaining top end? that might be a question to ask them.
12-07-2004, 09:55 PM
In my experience vendors are generally conservative when individuals try to mess with their stuff. Also, the particular tech may let his views cloud his perspective as it pertains to my agenda. He didnt details on the ups and downs which is why I am even following up on this. On my other cars, 2.3L turbo Fords, there are opponents who dont feel the 65MM TB is a good swap. I disagree and put them on all of mine and highly recommend to my club members.
Looking for someone with real world experience on the SVTF. A magazine articles had a good writeup and got like almost 4hp on a NA application and I suspect a FI would be even more but Im not about to drop $400+ on a 10 Hp gamble without real world input.
12-07-2004, 10:46 PM
Hey fstrdnu, since nobody answered your question, I will tell you what Richard Holdener in "High-Performance Ford Focus Builder’s Handbook" said; (even though his book is believed, by certain people on this Forum, to be questionable...)
He tested an SVT equipped with the M62 supercharger at 12 psi, and gain 12-13HP at the top end, and 8-10 ft-lbs from 4.5K to 6.5K RPM.
The theory is that with the supercharger, who sucks air in the unit, a larger TB is beneficial. But with a turbo, the air is pushed in, so the stock TB is good enough.
12-08-2004, 12:19 AM
An outstanding response. I like substantiated answers.
With only my 4-5 psi in my current setup I see less results than Mr. Holdener.
Not having read the book and only being a turbo guy with real world experience, a big TB is highly beneficial in a turbo setup.
12-08-2004, 12:30 AM
As they say, the more air the car can take in, and the faster it gets it out is always beneficial. BUT, in some aspects, were you gain efficiency, you loose Hp. Ie; I've heard 03-04 Cobras lose a little boost by removing the cats. Not sure if its true or not. I plan some testing with the JRSC set up - JRSC w/ and w/o ORP and JRSC w/ and w/o TB. Id like to see where the gains and losses are and how they would benefit/ hurt my driving style and weigh the options when I have cold hard facts.
Access to a dyno 24/7 is a wonderful thing!!