I'm fairly certain thats an s550 only issue, correct me if I'm wrong.
I'm fairly certain thats an s550 only issue, correct me if I'm wrong.
I'm interested in how these are holding up using the later design KDanner posted which basically eliminated the L/R clutch from applying on launch. I really would love to try it but I'm not versed enough to understand the consequences of eliminating that clutch in 1st gear.
The OWC holds to give you the 1st gear ratio, LR clutch only gives you engine braking. Stock calibration releases the LR at 2.5MPH when in drive range. The reason I change that to negative MPH in calibration is due to some solenoids being inverse from others, it makes the LR already off at 0 MPH which puts the solenoid in the proper condition for when the transbrake relays swap the circuits. This applies both the LR and INT clutches which are the only 2 hold clutches in the trans, meaning the steels are lugged into the case, not inside a drum. When the transbrake releases the only thing that is happening is the LR and INT are releasing. So, only difference from stock regarding the LR clutch is that it releases immediately instead of at 2.5 MPH, an almost imperceptible change.
I kinda figured it was for engine braking but wasn't confident enough to try it yet.
I really appreciate the response and info.
Apologies for the long delay in response. I haven't found a need to change any line pressure with the 2 relay setup. It works great on my personal car and have been 1.4 60' times. Several other cars I also tune that run 10's N/A haven't had an issue. Set the 2 step at 3,500 and go through standard launch procedure.
https://ibb.co/c5tGY6
Can somebody point me to the parts list and schematics needed for the 2 and 3 relay transbrakes? I have a 2011 GT and I ran the JMS for most of last year. It randomly failed at the end of last season. This year I bought a new one and the first 5 passes everything was great. The 6th pass yesterday the ECU never commanded 2nd gear and I bounced off the limiter at 7800 RPM's and then the car went into limp mode. DTC P0760. At first I wasn't sure if it was an issue with my transmssion. I couldn't get the code to go away. So I then connected the ECU wires back into each other and bam, code gone and car ran perfectly fine for the next 5 passes I did all footbraking off my 2-step.
Scared the crap out of me when this happened. I also installed L&M cams and a higher stall over the winter so I had no idea what happened on the track. I was scared at first I spun a bearing or something on the cam. Thankfully I was datalogging and I could see exactly what happened with the ECU not commanding 2nd gear and that it was just the limiter being hit.
So I'm going to just try the relays. So if wbt or kdanner or somebody else has the parts list and schematic?
Thanks guys!
Found the schematics in this thread with good info. Now I just need to hunt down the relays.
https://www.svtperformance.com/forum...after.1025019/
This is the best one to use.
Awesome thanks!
found the relays tonight at autozone and wired it up and it looks to be working great with very limited testing in my garage. I wired up the 2 relay initially and may test the 3 relay in the near future.
One question I have though, does anybody know how fast the relay switches? Is it milliseconds I hope and not hundredthds of a second? One thing I did like about the JMS version was that it was digital so I would assume it would be very fast. I'll be able to test for myself this weekend, but in the meantime does anybody know on average how fast this relay does switch?
I was trying to find the specs on it but can't find them any place
http://www.novitatech.com/?q=afterma...es-relays/rl45
I look at it like this. When the button is released the electromagnetic field ceases to exist and the spring loaded solenoid returns to its default position. Isn't this exactly what happens in an older transmission with a transbrake, other than those solenoids have to move much farther than the solenoid the relay contact is connected to? The relay contact that moves doesn't even need to get all the way back to its default position, as soon as it starts to move the circuit is broken and it is all hydraulics at that point.
Kdanner, so I did some track testing with the -2.5 value. I noticed the car crept on the brake and didn't seem to release right away and wouldn't 60ft. Any correlation or my trans just jacked up and not holding without both clutches being held? It's the JMS plug n play(I'm lazy) Here's a log of what it Did. You can see 1mph on the rear tires while on the brake. Also calculated Gear ratio goes off for a second once the brakes released which makes me think clutches slipping. Circle D 4C for reference.
Gear ratio drop didn't move.jpg
Last edited by bbrooks98; 06-10-2018 at 11:21 AM.
many car i data log n/a or supercharger with version 1 and 2 relay trans brake from kdanner there is a weird ratio occur before clutch are fully set without any impact on 0-60.. i saw 1.31 0-60 ... on this log... trans command gear 2.jpg i dont know set up on your car but timming seems to be low at 10 deg ...
Last edited by bob450; 06-10-2018 at 12:04 PM.