Safe HP level w/automatic

ddscz · Jan 22, 2009

The folks at FRPP suggest that anything over 400(flywheel) horsepower would destroy my transmission.It's an '07 with 3:73 gears used only on the street.What's your experience or thoughts? I would like 350-400 rwhp by going FI but don't want to destroy anything but the ego of Challenger and Camaro owners....Thanks

NastyStang113 · Jan 22, 2009

400-450 would be safe with a good tune.

An_08_GT_STANG · Jan 22, 2009

ddscz said:
The folks at FRPP suggest that anything over 400(flywheel) horsepower would destroy my transmission.It's an '07 with 3:73 gears used only on the street.What's your experience or thoughts? I would like 350-400 rwhp by going FI but don't want to destroy anything but the ego of Challenger and Camaro owners....Thanks

Thats not true dude i would recomend the Whipple SC by Ford..
Thatll RIP the pants off them, and your not the only one gearing up for that.. LOL
ITs going to be a blood bath lol
And this kit is estimate to put a guranteed 450RWHP on stock engine the kit has everything thats needed but this is one of the most powerful SC kits out there...

But yah check it out

Whipple Industries

Five Oh Brian · Jan 22, 2009

While FRPP discourages the use of the 500hp intercooled blower on automatics (offering just the 400hp non-cooled blower instead), a proper custom dyno tune would make it fine with your automatic transmission.

I am currently pushing 440hp at the flywheel with a Vortech V2 blower on my 07 GT automatic, and the transmission is doing fine. Heck, I have a 4,800 rpm stall converter & 4.10 gears, too, and the transmission is handling it all just fine. No scorched trans fluid, no problems, just consistent, hard/firm shifts at 6,400 rpm's in drive at wide-open-throttle.

klaw · Jan 22, 2009

I just sold an automatic to a guy who blew his within hours of installing a Procharger on his '07 GT. Apparently the '07's have different electronics than the earlier years and must be replaced with an '07. By fluke he found out I had one spare. I would heed FRPP's advice and keep the power lower. If you go with a Whipple, buy the HO to get the dual fuel pumps and intercooler but pulley it down to lower boost. Just my 0.02!

NastyStang113 · Jan 22, 2009

klaw said:
I just sold an automatic to a guy who blew his within hours of installing a Procharger on his '07 GT. Apparently the '07's have different electronics than the earlier years and must be replaced with an '07. By fluke he found out I had one spare. I would heed FRPP's advice and keep the power lower. If you go with a Whipple, buy the HO to get the dual fuel pumps and intercooler but pulley it down to lower boost. Just my 0.02!

Do you know exactly what's different? I'd be very curious about this ... Can a tuner work around it?

klaw · Jan 23, 2009

NastyStang113 said:
Do you know exactly what's different? I'd be very curious about this ... Can a tuner work around it?

I'm have no idea what the difference was other than it was an incompatability in the internal electronics and was therefore not fixable with a tuner. He actually needed an '07 model year tranny and I had one that I'd bought out of a wreck (for the engine actually). My car is a manual so I wasn't overly interested in the electronic issue. I will be talking to him in the next few days so will report back any additional info I can glean.

StonePony · Jan 23, 2009

400-450 would be safe with a good tune.

You base this opinion on what?
My 5R55s transmission was toasted after only 440 RWHP for about 3200 miles.
I wish I had only read your post before that happened so that I did not have to replace it.
(Nobody can guarantee that your tranny will hold that power, sorry. )

NastyStang113 · Jan 23, 2009

StonePony said:
You base this opinion on what?
My 5R55s transmission was toasted after only 440 RWHP for about 3200 miles.
I wish I had only read your post before that happened so that I did not have to replace it.
(Nobody can guarantee that your tranny will hold that power, sorry. )

I've seen transmissions fail at 330 rwhp. So, what's your point? I never said it would never fail but that seems to be the most rwhp that you can go before most guys experience problems.

Five Oh Brian · Jan 23, 2009

Might be worth pointing out that you can toast an automatic with a stock motor if you're hammering on it and abusing it, so there's not really a "safe" amount of power to be used as a rule.

Also, a whipple makes instant boost, which is likely much harder on driveline components than a centrifugal or turbo which generally eases into boost as rpm's climb.

And for those who've destroyed automatics already, I hope you didn't just install another factory stock trans. Level 10 and TCI make some super tough 5R55S transmissions for our cars that can withstand a lot more abuse. Heck, they probably don't cost much more - if any -than a stock transmission.

forensicsteve · Jan 23, 2009

I would be hesitant to use the terms "you'll be fine or safe". Too many variables and unknowns. There will always be a risk of causing damage to stock components under boost, and the risk just gets higher as the power level climbs.

So much also depends on the usage and that doesn't reveal itself on a dyno. Then 420 rwhp on one dyno maybe 520+ on another. There are 4 of us that live locally with forced induction. We've all blown something. Mate blew his stock motor at 510 rear wheel, another his stock transmission at 440. another his rearend also at 500+, and I blew a built motor trying 27 lbs boost. Since gone back down to 22lbs. So there's no guarantee of avoiding a misadventure.

jt217 · Jan 25, 2009

Whipple now makes a 7psi intercooled kit for the Mustang GT auto which puts out 475 hp which was designed with Ford Racing. I am sure that if the auto would not handle it they Ford wouldn't warranty it. I have a Paxton on my 2006 GT and have not experienced any problems as of yet but my concern for the trans is the reason I chose a centri supercharger instead of roots or twin screw. My dyno run was 428whp and 403tq.

ddscz · Jan 25, 2009

jt217 said:
Whipple now makes a 7psi intercooled kit for the Mustang GT auto which puts out 475 hp which was designed with Ford Racing. I am sure that if the auto would not handle it they Ford wouldn't warranty it. I have a Paxton on my 2006 GT and have not experienced any problems as of yet but my concern for the trans is the reason I chose a centri supercharger instead of roots or twin screw. My dyno run was 428whp and 403tq.

Would you happen to know the part number for this kit? Does it come through FRPP? Thanks

Invective · Sep 9, 2012

ddscz said:
Would you happen to know the part number for this kit? Does it come through FRPP? Thanks

M-6066-MGT475

The pdf instructions are most interesting.

http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=11414

LOL!!! I realize this is an old thread but this same kit is on my 'wish list'! Forum search brought me here. I've read recently where the 5R55S transmission is good for 500 hp; don't recall if that's rwhp or net fwhp.

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