How much power did you lose going TH400?
11-26-2008, 05:06 PM
#1
How much power did you lose going TH400? Figured this would be good discussion for the holiday downtime. I swapped in a TH400 in place of my 4L60E, lost about 125 RWHP peak. Went from 740 to 615, I figured I'd lose 100 or so. Just curious if anyone had a similar experience, I'd like to hear what you lost. I fully expect the car to be faster anyway, and this RMVB is fun on the street. I can finally get on it in 3rd at low speeds and not blaze the tires. I'll probably drop the rear gear from its current 3.73 to something around 3.23 if I can. Can't wait to let this thing fly on the 2 step and trans brake!
11-26-2008, 05:42 PM
#4
11-26-2008, 06:29 PM
#5
740rwhp does seem a bit high for an auto + D1SC car. I bet they were locking the converter to get those type of numbers, right? A TH400 isn't the best trans for dyno racing. Its funny ,but I see it happening all the time. People post their M6 or locked A4 dyno numbers all over the place. Then once they swap over to Th400, their duno numbers become more hush hush. 
Maybe your TH400 converter is realy loose so it lost a little more, but I wouldn't loose any sleep over it. My old setup, which was D1SC,402, TH400 did around 590 on a mustang dyno. That was with the blower maxed out. So your numbers seem just about right.
Maybe your TH400 converter is realy loose so it lost a little more, but I wouldn't loose any sleep over it. My old setup, which was D1SC,402, TH400 did around 590 on a mustang dyno. That was with the blower maxed out. So your numbers seem just about right.
11-26-2008, 07:57 PM
#6
my car makes over 750+ rwhp yet only dynos 500 rwhp, dynos lie. Don't worry about the numbers, they mean nothing as long as your tune is good. I don't worry about my missing 250rwhp on the dyno, I know my junk is huge and so does everyone I use it on.
11-26-2008, 08:06 PM
#7
I have a turbo 03 cobra that made 800rwhp on 19 psi on the 6 speed.
We put it back on the dyno with a unlocked th400 and it made 560 rwhp at the same boost. The car picked up at the track though.
This same car traps 147 in the 1/4 at 3700 lbs on 23 psi...which is 680 rwhp on the dyno.
We put it back on the dyno with a unlocked th400 and it made 560 rwhp at the same boost. The car picked up at the track though.
This same car traps 147 in the 1/4 at 3700 lbs on 23 psi...which is 680 rwhp on the dyno.
Trending Topics
11-26-2008, 08:21 PM
#8
Oh I'm not worried about the numbers, the only reason it was even dyno'd was to verify the tune. I'm running a 4000 stall, and a fairly low buck trans (no roller bearings or fancy tricks). On my first pull the timing was wrong (M6 tune not flashed in yet) so I only had the "park" timing table and made like 365 RWHP. I was like "well, that sucks". Once we corrected the tune it was fine.
I'm really just hoping for improved short times. My best on the 4L60E was a 1.54 (footbrake). Now with a looser convertor and a TB/2 step, I expect to have wheelie issues. This car should sixty foot in the 1.3x's, putting me in the mid 9's I'd say (went 10.14 at 139.3 with a 1.64 60'). Too bad I gotta wait for the spring to run it....
I'm really just hoping for improved short times. My best on the 4L60E was a 1.54 (footbrake). Now with a looser convertor and a TB/2 step, I expect to have wheelie issues. This car should sixty foot in the 1.3x's, putting me in the mid 9's I'd say (went 10.14 at 139.3 with a 1.64 60'). Too bad I gotta wait for the spring to run it....
11-27-2008, 10:27 AM
#9
TECH Resident
iTrader: (64)
Join Date: Jul 2005
Location: sneaking in your back door as you leave!/cartersville ga
Posts: 908
Likes: 0
Received 0 Likes
on
0 Posts
dyno
take it to the track
ive heard 20% to 25% for a 80/400, i think around 15% on a 60/350. and even less in a glide like 10%. and 6-speed dyno number impress keyboard jockeys
take it to the trackive heard 20% to 25% for a 80/400, i think around 15% on a 60/350. and even less in a glide like 10%. and 6-speed dyno number impress keyboard jockeys
11-27-2008, 11:10 AM
#10
TECH Enthusiast
iTrader: (28)
Join Date: Apr 2008
Location: Grayson, KY 41143
Posts: 591
Likes: 0
Received 0 Likes
on
0 Posts
I actually just had the exact conversation at a machine shop yesterday with a long time gear head. He told me that on average a 400 turbo will eat 75hp due to rotational mass. I guess the rest really depends on slippage of your torque converter or blow through. Most good converters advertise like 2-4% I think.
11-27-2008, 11:21 AM
#11
Alot of 400 setups can't even be dyno'd per se because they will blow through the convertor. You have to understand how dyno's work to understand why TH400's don't make big numbers on a dyno. Look at it like this: The dyno said my car was going like 105 MPH at the top of 3rd gear. Obviously in the real world that would have been 160+ MPH. It can't account for slippage. Thats why I said the only reason to even dyno it was to check the tune.
I'd guess a TH400 eats 25%-30%, based on what I've seen. They can be built to eat less power, but it gets pricey.
I'd guess a TH400 eats 25%-30%, based on what I've seen. They can be built to eat less power, but it gets pricey.
