non trans break launch boost??

[postal]

I' only able to generate between 5 to 7 #'s of boost on my brakes (e-break included). I have a T63E turbo and an Art Carr 9". My motor is a 103k mile non rebuilt engine so I'm sure building boost with this set up may be a little harder than for some other people. I was just wondering what kind of boost you other guys can build on the breaks to see if I'm in the ball park or not. Over all I'm pretty pleased with the performance of my car. I only have 2 full passes with the slicks on. The last run was 12.04 sec @ 116.3 mph. I had a slight stumble in the motor d/t running to rich. I now have the car leaned out and it sure feels strong now. Once I can have a free weekend where it isnt raining Ill be back out to the track looking for an 11.xx run. BTW my 60' times seam to be stuck in the 1.80 to 1.82 range( 4 launches on slicks). I figure if I can 60' in the mid 1.6 range and run 116 or so I would have to be solidly in the 11's wouldnt I?
Thanks in advance: Jason

 

[Hi-psi]

With stock rear suspension, 255/50/16 BFG Drag Radials, a TE-60, and Art Carr 9", I launched off the e-brake at 3-4psi and put down low 1.60's. Only options for launching with more boost are drum brakes or transbrake. I went with a transbrake and made 1 pass before my Art Carr tranny broke. So needless to say I'd recommend drum brakes.

 

[postal]

hmmm.....3 to 4 psi launch and 1.6 60's for you and 5 to 7 psi launch and 1.8's for me. I think I'm running a bit fat on the bottom so maybe I'm spooling up a little to slow after the launch? I'm also running pretty conservitive with my timming. I have a translator plus and ive tweaked it out to where I run now. This was by using the straight across the board setting changes. ( -4% fuel, -2 degrees timming) It does have settings to take more out on bottom or top than just a straight %. Maybe Ill mess with these a bit and see if i can improve the 60' times. I'm kind of leary of messin with my settings too much though. Ive been waiting all summer for fall to get here so I can make some of those "COOL AIR" runs. I would hate to break some thing now just as the cool weather is starting to set in.

Thanks for your response: Jason
BTW my slicks hook good so they are not suspect at this point.

 

[webleyaz]

Hi-psi's right. Drums are the way to go. Much less chance of breaking stuff since there's no "shock" to the rear end. I saw 18 psi on my gauge the other day 5 feet from a wall at my shop. I do have to use the E-brake also, I think. Haven't tried w/o. I'm not sure if the tires would stick if I actually tried an 18# launch, but I'll let you know. 14#s of boost was good for 1.52 and 1.53 60' times on 11.5 ET streets at 13 psi. Amazing feeling. The rear suspension is stock aside from the drums. Front sway bar is omitted. No other suspension mods. I thought about an air bag for a while but had a hard time finding one that would fit so I gave it up.

 

[1badTTA]

Hey Chris, whats up, feel like swinging by htis weekend to try and get mine running again? got the motor set in it and you could help immensley by bringing your car by to compare to when hooking everything up.
let me know.
Rick, we met at the BOP show, I have Bob's old car

 

[webleyaz]

Hey Rick,
I sent you an E-mail. I forgot to ask which car you need to compare to. There's not much difference except for the intercoolers.

 

[1badTTA]

Drums on a TTA

Hey chris, just to get back on subject, drums on a TTA are a little different than on a GN. There are alot of posts about what to do about the drums on the GN's/TR's and they have a different braking system than the TTA's. you need to keep in mind that the TTA's came with insane rear disks (I know, I went sliding sideways @120mph when a Semi changed lanes) and the disks provide more rolling friction than drums but are not self engaging (apply more stopping pressure than you apply fluid pressure) and therefore require ALOT MORE fluid pressure at the calipers than a drum setup is used to. By converting a TTA to drums you will end up with a dragstrip warrior that will hold TONS of boost on the line but will have adverse effects on the street at high speeds. If your goals are to run the car on the strip most of the time, by all means convert it over to drums, you have the best braking system to comvert for strip use, but if you ever plan to roadrace the car or just want to drive it on the street and go to the strip twice a year, leave it with the factory 1LSE brakes.

 

[Hi-psi]

Or install a proportioning valve.

 

[SPower6]

On the subject of rear drum brakes, what is involved in doing this? Please list needed parts and any tricks for installation? TIA
Best regards,
Jeff

 

[Hi-psi]

Jeff,

You talking in reference to putting them on the stock rear or on a 9"? For the stock rear I would suggest going boneyard hunting. There should be plenty of 9-bolts out there with drum brakes. Easisest thing would be to get the whole housing. Otherwise I would guess you would need the backing plates, drums, wheel cylinders, springs & accesories, and maybe the brake lines on the rear itself. As I stated in the previous post, also smart to get a proportioning valve to control the front/rear brake bias.

 

[webleyaz]

You will need an entire rearend or housing that came with drum brakes. They will not swap to a disc housing. Actually it is not common to find 9-bolts w/o discs, I'm not even sure there are any at all. I'm running a 10-bolt from an '89 6-cyl. car that came with 3.27 and posi and drums. The rear end swap is basically a no-brainer. The bitch is the proportioning valve unless you use the one that came in the cer you're getting the axle from. I wanted adjustability but now that I have it I'm not sure it was worth it. The proportioning valves should swap easily too. So far this 10-bolt has survived some pretty hard launches but I'll install A/M axle shafts soon since they are required in the 11s here.

 

[SPower6]

Thanks Robert and Chris for your replies! Yes this is for a stock rear. Have a good weekend
Best regards,
Jeff