Trans help with front mount turbo C5
04-11-2016, 02:15 AM
#1
Burning Brakes
Thread Starter
Trans help with front mount turbo C5
I'm throwing the help flag on this one because I've got zero experience with building transmissions. Here's the long and the short of it. Originally I started out with a rear mount turbo very with a 4L60E that my buddy built. He's a very experienced performance transmission builder. Trans worked great with the rear mount and made 565 RWHP. I decided to go with an aftermarket built 390 CI motor and larger front mount turbo. PTC custom torque converter. While EVERYTHING was apart, my buddy told me to bring the trans over for a freshen and update. After doing his thing I finished the build and had it tuned. It made pretty much the same power with less boost, less timing, and no meth. The night I had it tuned it rained so a test drive wasn't possible . When I finally drove it a few days later, it would bang the limiter every time on the 1-2 shift at WOT. At about 80% throttle it would shift fine. Tuner figured it needed an adjustment but I didn't make it back for a tune adjustment because I knew I was going to make some changes and be back soon for an E85 tune.
I redid the down pipe, upped my fuel system game, got an electric boost controller then filled her with E85 for an E85 tune.
A week before my scheduled tuning session I completely destroyed the clutches in the trans. while adjusting the boost controller. My buddy said I even wrecked the forward 3-4 clutch pack. He was able to get it back to me in a couple days but couldn't identify why it burnt up. The trans had less than 1000 street miles and 6-7 dyno pulls. Plus a few hard over-boosts during boost controller testing.
After the dyno it made a little more power but with even less boost (10lbs). Made 585 RWHP. The trans performed great on the dyno and only reached about 185*. After the tune I test drove it and it still won't hit the 1-2 shift at WOT. During normal driving it performs fantastically . The tuner put in 3 trans tunes from cars he knows work great then he built another tune specifically for my car. Still nothing. Logged every test drive. Even commanding the trans to shift super early it still won't shift. In disbelief, he took it for a ride and nothing. He was able to manually shift the 1-2 and he said it performed very nicely but from 2-3 he said it felt like it laid over. It was 1am and I heard the pass, it sounded great but a trans that doesn't shift doesn't cut it.
Any ideas that I could pass along to my trans guy would be great. I really don't have $4500 to go with an FLT or RPM trans. 🤑
I redid the down pipe, upped my fuel system game, got an electric boost controller then filled her with E85 for an E85 tune.
A week before my scheduled tuning session I completely destroyed the clutches in the trans. while adjusting the boost controller. My buddy said I even wrecked the forward 3-4 clutch pack. He was able to get it back to me in a couple days but couldn't identify why it burnt up. The trans had less than 1000 street miles and 6-7 dyno pulls. Plus a few hard over-boosts during boost controller testing.
After the dyno it made a little more power but with even less boost (10lbs). Made 585 RWHP. The trans performed great on the dyno and only reached about 185*. After the tune I test drove it and it still won't hit the 1-2 shift at WOT. During normal driving it performs fantastically . The tuner put in 3 trans tunes from cars he knows work great then he built another tune specifically for my car. Still nothing. Logged every test drive. Even commanding the trans to shift super early it still won't shift. In disbelief, he took it for a ride and nothing. He was able to manually shift the 1-2 and he said it performed very nicely but from 2-3 he said it felt like it laid over. It was 1am and I heard the pass, it sounded great but a trans that doesn't shift doesn't cut it.
Any ideas that I could pass along to my trans guy would be great. I really don't have $4500 to go with an FLT or RPM trans. 🤑
05-30-2016, 09:15 PM
#2
Burning Brakes
Thread Starter
I'm dying a slow death here. My trans guy thought that by opening some passages inside the valve body that the issue would be fixed. He replaced the burnt clutches and opened up the valve body. STILL NOT SHIFTING!!! Anybody got any suggestions ? Could the issue be in the converter ?
Last edited by junk c5; 05-30-2016 at 09:18 PM.
05-31-2016, 08:48 AM
#3
Le Mans Master
You need a new trans tuner it sounds like to me...it seems like it's not hitting the shift targets in the map, probably the mph target. Lower the shift rpm to like 5000 and lower the shift mph a few mph and see what it does.. If the shift targets are that low, and it's still crashing into the limiter, it's probably something else in the trans..
Also, dynoing a 4l60 is the kiss of death for them, that's what fries the 3-4 clutches so fast. When the dyno guy jumps on the dyno brake to slow the drum/engine down, there is low line pressure applied to the clutches in the trans because the throttle is closed...this forces the clutches to slip trying to slow the engine down using the drivetrain.
Your car sounds awesome tho!
Also, dynoing a 4l60 is the kiss of death for them, that's what fries the 3-4 clutches so fast. When the dyno guy jumps on the dyno brake to slow the drum/engine down, there is low line pressure applied to the clutches in the trans because the throttle is closed...this forces the clutches to slip trying to slow the engine down using the drivetrain.
Your car sounds awesome tho!
05-31-2016, 09:21 AM
#4
Burning Brakes
Thread Starter
You need a new trans tuner it sounds like to me...it seems like it's not hitting the shift targets in the map, probably the mph target. Lower the shift rpm to like 5000 and lower the shift mph a few mph and see what it does.. If the shift targets are that low, and it's still crashing into the limiter, it's probably something else in the trans..
Also, dynoing a 4l60 is the kiss of death for them, that's what fries the 3-4 clutches so fast. When the dyno guy jumps on the dyno brake to slow the drum/engine down, there is low line pressure applied to the clutches in the trans because the throttle is closed...this forces the clutches to slip trying to slow the engine down using the drivetrain.
Your car sounds awesome tho!
Also, dynoing a 4l60 is the kiss of death for them, that's what fries the 3-4 clutches so fast. When the dyno guy jumps on the dyno brake to slow the drum/engine down, there is low line pressure applied to the clutches in the trans because the throttle is closed...this forces the clutches to slip trying to slow the engine down using the drivetrain.
Your car sounds awesome tho!
06-03-2016, 02:46 PM
#5
Safety Car
Make sure the tcc isn't slipping. That creates a lot of heat and will take out the trans. Usually 4th and then 3rd gear go first. Get a bigger cooler too. 185* is about as hot as you'd ever wanna see it. The dyno isn't that hard on the trans. I imagine it may be hotter on the road. After multiple pulls while tuning my trans temp was 144* putting down 830rwhp.
Last edited by C5Natie; 06-03-2016 at 02:48 PM.
06-04-2016, 02:35 AM
#6
Le Mans Master
You need a new trans tuner it sounds like to me...it seems like it's not hitting the shift targets in the map, probably the mph target. Lower the shift rpm to like 5000 and lower the shift mph a few mph and see what it does.. If the shift targets are that low, and it's still crashing into the limiter, it's probably something else in the trans..
Also, dynoing a 4l60 is the kiss of death for them, that's what fries the 3-4 clutches so fast. When the dyno guy jumps on the dyno brake to slow the drum/engine down, there is low line pressure applied to the clutches in the trans because the throttle is closed...this forces the clutches to slip trying to slow the engine down using the drivetrain.
Your car sounds awesome tho!
Also, dynoing a 4l60 is the kiss of death for them, that's what fries the 3-4 clutches so fast. When the dyno guy jumps on the dyno brake to slow the drum/engine down, there is low line pressure applied to the clutches in the trans because the throttle is closed...this forces the clutches to slip trying to slow the engine down using the drivetrain.
Your car sounds awesome tho!
Make sure the tcc isn't slipping. That creates a lot of heat and will take out the trans. Usually 4th and then 3rd gear go first. Get a bigger cooler too. 185* is about as hot as you'd ever wanna see it. The dyno isn't that hard on the trans. I imagine it may be hotter on the road. After multiple pulls while tuning my trans temp was 144* putting down 830rwhp.
06-04-2016, 10:31 PM
#8
Burning Brakes
Thread Starter
I had my trans guy come by yesterday and we put his pressure gauge in the service test port on the drivers side of the trans then took it for a ride. He said the idle and pressures in all gears while stopped looked normal. Pressure at WOT was around 225 - 230lbs. He also hooked up his scanner and he watched the scanner while I drove. He's stumped because he said everything appeared normal. The DIC and his scanner had the trans temp at 179* after 15 minutes of cruising and a couple hard hits. He's been getting his building tips from somebody else because he met a trans guy in California who supposed to know how to get a 4L60E to handle power. The trans worked great before he started taking his guys advise.
The trans is 15 minutes from being on the ground. I need a hand physically getting the cradle and everything that comes with it down. Chances are pretty good I'll drop the trans at FLT Monday afternoon. Unfortunately FLT is backed up 2-3 weeks. ��
The trans is 15 minutes from being on the ground. I need a hand physically getting the cradle and everything that comes with it down. Chances are pretty good I'll drop the trans at FLT Monday afternoon. Unfortunately FLT is backed up 2-3 weeks. ��
06-05-2016, 10:49 AM
#10
Safety Car
I had my trans guy come by yesterday and we put his pressure gauge in the service test port on the drivers side of the trans then took it for a ride. He said the idle and pressures in all gears while stopped looked normal. Pressure at WOT was around 225 - 230lbs. He also hooked up his scanner and he watched the scanner while I drove. He's stumped because he said everything appeared normal. The DIC and his scanner had the trans temp at 179* after 15 minutes of cruising and a couple hard hits. He's been getting his building tips from somebody else because he met a trans guy in California who supposed to know how to get a 4L60E to handle power. The trans worked great before he started taking his guys advise.
The trans is 15 minutes from being on the ground. I need a hand physically getting the cradle and everything that comes with it down. Chances are pretty good I'll drop the trans at FLT Monday afternoon. Unfortunately FLT is backed up 2-3 weeks. ��
The trans is 15 minutes from being on the ground. I need a hand physically getting the cradle and everything that comes with it down. Chances are pretty good I'll drop the trans at FLT Monday afternoon. Unfortunately FLT is backed up 2-3 weeks. ��
Last edited by helga203; 06-05-2016 at 10:50 AM.
The following users liked this post:
junk c5 (06-05-2016)
06-05-2016, 10:09 PM
#11
Burning Brakes
Thread Starter
That's kick *** man, thx for the offer. I'm still on the south side of Chicago ... Once I get it right I'll shoot u a message when I hit the local street racing spots.
06-05-2016, 10:10 PM
#12
Burning Brakes
Thread Starter
06-06-2016, 06:04 AM
#13
Safety Car
I ditched my BM Supercooler and went with one big Tru-Cool. I havent even needed a fan for it yet whereas I did with the BM. Im seeing at least 20*+ lower temps with ambient are cooling alone.
It has a higher btu rating than the biggest BM cooler.
Tru-Cool Max LPD47391
http://www.ebay.com/itm/Tru-Cool-Max-40-000-GVW-Transmission-Oil-Cooler-Low-Pressure-Drop-OC-4739-1-/321995823346?_trksid=p2141725.m3641.l6368
It has a higher btu rating than the biggest BM cooler.
Tru-Cool Max LPD47391
http://www.ebay.com/itm/Tru-Cool-Max-40-000-GVW-Transmission-Oil-Cooler-Low-Pressure-Drop-OC-4739-1-/321995823346?_trksid=p2141725.m3641.l6368
06-06-2016, 06:50 PM
#15
Safety Car
