New best but need input
07-22-2007, 08:00 PM
#1
New best but need input We finally got a non-100 degree street night so I made two passes. 2nd one was the best, 10.37 @ 137.78 1.65 60'. This was leaving off of the t-brake at 10psi and the tires didn't spin so i don't know what's going on...I've pulled a few 1.5's with the six speed on the same ET streets. I can't tell if something is up with my stall as it seems like i am really pushing through it or if my tranny is slipping (RMVB TH400). My stall is a 3300rpm converter but it only drops about 500rpms when i shift from 1-2 or 2-3 at WOT....is this normal?
Anyways, i am still running a stock engine minus ls6 intake, cam and springs on 93 octane and really want to get a 9sec pass as is...i think the mph is good for one if i could just 60' better. I was all set to get some taller hoosiers but now i don't know what to do. Any suggestions? I don't want to take any weight out of the car as i like all my creature comforts.
Thanks for any input.
-Jarrod
Anyways, i am still running a stock engine minus ls6 intake, cam and springs on 93 octane and really want to get a 9sec pass as is...i think the mph is good for one if i could just 60' better. I was all set to get some taller hoosiers but now i don't know what to do. Any suggestions? I don't want to take any weight out of the car as i like all my creature comforts.
Thanks for any input.
-Jarrod
07-23-2007, 08:49 PM
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What's the converter specs? Great run but from what you've posted the converter is too loose.....most common mistake converter companies make on turbo apps.
07-24-2007, 12:55 PM
#6
Black98Ws6ta: Unfortunately I did not log those passes but from best i can tell by looking at my tach as i cross the line, it's around 6150-ish-rpms. It doesn't really gain a whole lot of rpms from the 1/8 to the 1/4...maybe 300-400...I was told that's normal..yes?
Onfire: Thanks for the props...converter specs, it's a Transmission specialties 3000-3300 stall, 10" and supposedly good for up to 850hp.
FWIW, a friend of mine thinks its because i am running 3.08 gears...but my Th400 is from a truck so i have a low first gear...so i was hoping the two would cancel eachother out to some extent.
Thanks for the input guys.
-Jarrod
Onfire: Thanks for the props...converter specs, it's a Transmission specialties 3000-3300 stall, 10" and supposedly good for up to 850hp.
FWIW, a friend of mine thinks its because i am running 3.08 gears...but my Th400 is from a truck so i have a low first gear...so i was hoping the two would cancel eachother out to some extent.
Thanks for the input guys.
-Jarrod
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07-24-2007, 02:19 PM
#9
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How long do you stay in each gear Jarrod? One symptom of a converter being too lose is that you shift say at 6500, and the rpms drop 500 rpms, and you are only in your powerband for 500 rpms. So you run through the gears fast. That's not bad for an NA race car with small cubes you might need that, but for a big torque turbo car with a narrow power band, you might want to stay in that power band longer, like 1000 rpms or a bit more.
07-24-2007, 03:07 PM
#11
PSJ: I haven't dynoed with the auto but with the 6spd my hp was over 600 by 5500rpms and never really started to drop at 6500 when i let off. Peak tq on the dyno was ~4500rpms but the car was real laggy so I think on the street with more load and espcially now since i shortened/wrapped the pre-turbo side of the kit, peak tq should be quite a bit lower and be higher than the dynoed 588.
My thinking is exactly the same as yours, I would think it would be better for me to stay in my powerband longer with the area under the curve i have...I shift out of 1st (around the 200' mark) and 2nd rather quick and am in 3rd by the 1/8 but the rpms are around 5800ish and climb verrrry slowly up to 6150-6200 by the 1/4.
Black98ws6ta: What rpm do you launch at?
I just got off the phone with Trans specialties tech and he said i may be asking too much of my street/strip converter...and may have to go with an 8" to get what i want at the track but to me that sounds fishy, plus it's not street friendly. He did ask me to try launching at a lower stall speed, say around 3300 to 4200 instead of letting the converter flash as high as it will go with me on the t-brake and wot throttle.
Other turbo/t-brake/auto people, are you able to get the converter to rev past it's stall with full throttle applied and almost full boost?
I have a video of two runs from a few weeks ago but can't get my computer to read the camera's little dvd otherwise i would put it up so you could see/hear the car....it honestly sounds like I am slipping the clutch from the starting line to out past the 60' marker.
Thanks again,
-Jarrod
My thinking is exactly the same as yours, I would think it would be better for me to stay in my powerband longer with the area under the curve i have...I shift out of 1st (around the 200' mark) and 2nd rather quick and am in 3rd by the 1/8 but the rpms are around 5800ish and climb verrrry slowly up to 6150-6200 by the 1/4.
Black98ws6ta: What rpm do you launch at?
I just got off the phone with Trans specialties tech and he said i may be asking too much of my street/strip converter...and may have to go with an 8" to get what i want at the track but to me that sounds fishy, plus it's not street friendly. He did ask me to try launching at a lower stall speed, say around 3300 to 4200 instead of letting the converter flash as high as it will go with me on the t-brake and wot throttle.
Other turbo/t-brake/auto people, are you able to get the converter to rev past it's stall with full throttle applied and almost full boost?
I have a video of two runs from a few weeks ago but can't get my computer to read the camera's little dvd otherwise i would put it up so you could see/hear the car....it honestly sounds like I am slipping the clutch from the starting line to out past the 60' marker.
Thanks again,
-Jarrod
07-24-2007, 03:22 PM
#12
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I'm changing my converter right now, and based on research, you might run an 8" converter with a blower but not with a turbo. The blower setup mimics NA in that the power is gradual, so part of the game is to run a converter that gets you up in your power band. KP runs a ATI Treemaster 8" converter that makes his car leave hard and run good... A blower car runs like a 600ci big block (my analogy).
A turbo car is different. I'm a turbo newb, but the power can come on real big at lower rpms and be unusable because you can't hook it. I'm starting to think that turbo is a whole different animal, because you really aren't looking to rush through your power like NA or blower, you want to stay in your power band which might be flat as a pancake.
I'm pulling my TCT converter because it was originally spec'd for my YSi. Concern is that it's too loose to work well at the track.
A turbo car is different. I'm a turbo newb, but the power can come on real big at lower rpms and be unusable because you can't hook it. I'm starting to think that turbo is a whole different animal, because you really aren't looking to rush through your power like NA or blower, you want to stay in your power band which might be flat as a pancake.
I'm pulling my TCT converter because it was originally spec'd for my YSi. Concern is that it's too loose to work well at the track.
07-25-2007, 12:17 PM
#13
Guys, be careful going with those 8" converters. The small converters just don't have enough holding power if you're making alot of horsepower. We couldn't get my 9.5" converter tight enough, so I had to switch to a 10.5".
Mike
Mike
07-25-2007, 03:17 PM
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Originally Posted by RICE ETR
PSJ: I haven't dynoed with the auto but with the 6spd my hp was over 600 by 5500rpms and never really started to drop at 6500 when i let off. Peak tq on the dyno was ~4500rpms but the car was real laggy so I think on the street with more load and espcially now since i shortened/wrapped the pre-turbo side of the kit, peak tq should be quite a bit lower and be higher than the dynoed 588.
My thinking is exactly the same as yours, I would think it would be better for me to stay in my powerband longer with the area under the curve i have...I shift out of 1st (around the 200' mark) and 2nd rather quick and am in 3rd by the 1/8 but the rpms are around 5800ish and climb verrrry slowly up to 6150-6200 by the 1/4.
Black98ws6ta: What rpm do you launch at?
I just got off the phone with Trans specialties tech and he said i may be asking too much of my street/strip converter...and may have to go with an 8" to get what i want at the track but to me that sounds fishy, plus it's not street friendly. He did ask me to try launching at a lower stall speed, say around 3300 to 4200 instead of letting the converter flash as high as it will go with me on the t-brake and wot throttle.
Other turbo/t-brake/auto people, are you able to get the converter to rev past it's stall with full throttle applied and almost full boost?
I have a video of two runs from a few weeks ago but can't get my computer to read the camera's little dvd otherwise i would put it up so you could see/hear the car....it honestly sounds like I am slipping the clutch from the starting line to out past the 60' marker.
Thanks again,
-Jarrod
My thinking is exactly the same as yours, I would think it would be better for me to stay in my powerband longer with the area under the curve i have...I shift out of 1st (around the 200' mark) and 2nd rather quick and am in 3rd by the 1/8 but the rpms are around 5800ish and climb verrrry slowly up to 6150-6200 by the 1/4.
Black98ws6ta: What rpm do you launch at?
I just got off the phone with Trans specialties tech and he said i may be asking too much of my street/strip converter...and may have to go with an 8" to get what i want at the track but to me that sounds fishy, plus it's not street friendly. He did ask me to try launching at a lower stall speed, say around 3300 to 4200 instead of letting the converter flash as high as it will go with me on the t-brake and wot throttle.
Other turbo/t-brake/auto people, are you able to get the converter to rev past it's stall with full throttle applied and almost full boost?
I have a video of two runs from a few weeks ago but can't get my computer to read the camera's little dvd otherwise i would put it up so you could see/hear the car....it honestly sounds like I am slipping the clutch from the starting line to out past the 60' marker.
Thanks again,
-Jarrod
Yep, that's going the wrong direction for a turbo converter.
07-26-2007, 06:03 AM
#17
Mike, I had heard the same thing about 8" converters as well as they are a no-go for the street....right?
The tech at trans specialties said he could maybe give me 200rpms worth by reworking the converter but that's not even close to being enough.
Ok so the consensus is I need another converter. I was thinking Yank or the like. Anyone have any suggestions on what I should get? Stall rpm, size, etc?
Thanks guys for all the help,
-Jarrod
The tech at trans specialties said he could maybe give me 200rpms worth by reworking the converter but that's not even close to being enough.
Ok so the consensus is I need another converter. I was thinking Yank or the like. Anyone have any suggestions on what I should get? Stall rpm, size, etc?
Thanks guys for all the help,
-Jarrod
