What could cause a trans to rob power?
Thread Starter
On The Tree
Joined: Dec 2001
Posts: 153
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From: DFW area, tx
What could cause a trans to rob power? I don't really understand alot about transmissions and im sure some of you have seen a few of my recent post trying to figure this out. I put down very low numbers after cam and vig 2800 intall. After having LGM do a few test we've narrowed it down to being caused by faulty exhaust and problems in the transmission. So how does a trans. rob power? I only gained like 15hp and 10lbs. of torque. I drives and shifts fine with normal driving, but i've gotten on it twice and it seems like it's slipping a bit from 1-2. Im going to have a tranny shop look at it but I was just curious.
Thread Starter
On The Tree
Joined: Dec 2001
Posts: 153
Likes: 0
From: DFW area, tx
Re: What could cause a trans to rob power? My mods include G5 cam, vig 2800, MAC headers w/ cats, Borla, Lid. Before the cam and convertor I pulled 306 rwhp and 330 rwtq. Afterwards I only pulled 322hp and 340tq. It was even dynod again after that and I put down even less!! They checked my engine to see if it was ok (compression, leak down test etc).
Thanks.
<small>[ November 06, 2002, 02:44 PM: Message edited by: DrowningMan ]</small>
Thanks.
<small>[ November 06, 2002, 02:44 PM: Message edited by: DrowningMan ]</small>
Re: What could cause a trans to rob power? If your trans was overfilled during the converter swap, it will cost you rwhp. I've seen 10 rwhp loss by being overfilled by 1 quart. The internals have to churn through lots of oil when the trans is overfilled. The extra drag robs power.
Another thing to think about: Your Vig 2800 will cost you around 10-15 rwhp over the stock converter. If you add that number back, you will find that your mods gained you more than you thought. I assume you haven't track tested the before vs. after difference. If you had, you might be very surprised on how much faster you really are and not question the small dyno increase.
Also, the higher stall converter will soften the shift firmness on your 1-2 shift, making it feel like the trans is slipping. It's probably not.
Another thing to think about: Your Vig 2800 will cost you around 10-15 rwhp over the stock converter. If you add that number back, you will find that your mods gained you more than you thought. I assume you haven't track tested the before vs. after difference. If you had, you might be very surprised on how much faster you really are and not question the small dyno increase.
Also, the higher stall converter will soften the shift firmness on your 1-2 shift, making it feel like the trans is slipping. It's probably not.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
Thread Starter
On The Tree
Joined: Dec 2001
Posts: 153
Likes: 0
From: DFW area, tx
Re: What could cause a trans to rob power? Yeah, i've heard that about the convertor dragging down the hp levels. but that second time it was dyno it went down even less, about 10hp less. Perhaps it might just be my exhaust doing all this. But only gaining 16hp and 10lbs of torque still doesn't seem right.
Thanks for the input!
Thanks for the input!
Re: What could cause a trans to rob power? Patrick G is right. I just got my S2/X1 package done. It dyno`d about 410rwhp,A4 Vig 3200, 12-bolt 3.73. Friend of mine has the same package with a M6 and a 10-bolt 3.42 gears and dyno`d 445rwhp. I`m about 35rwhp short of him on same year cars. But I will say on the street my car pulls like a Mother! Everything cost power on the dyno for A4 drivetrain. But on the track you make up for it. Remember Dyno kings can make Track queens!! Dyno numbers arn`t everything! The track does! Also did you get any tuning with your cam etc. You might need it to see full use of your set-up! I hope this helps! <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />
Thread Starter
On The Tree
Joined: Dec 2001
Posts: 153
Likes: 0
From: DFW area, tx
Re: What could cause a trans to rob power? Yeah, I did get tuning with the cam. I realize that Im not going to be putting down the same numbers as most given Im a '98 A4, but 16hp and 10lbs of torque just didn't seem right. But thanks for the replies, helps me put things in perspective. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
