pneumo
20+ Year Contributor
- 3,763
- 59
- Oct 19, 2002
-
Bay Area,
California
Yes that's right, I'm going for it again!
Exactly two weeks ago I finished rebuilding my motor, head, and tranny. So I figured, why not try for some fast times on the 14b again? Here's what happened last time, www.dsmtuners.com/forums/drag-strip/236131-11-second-14b.html?
This time my goal is to go faster than 11.64 on a 14b.
After all I did to the car last time, where would I get that much more speed/power? I already crossed the line at 6300rpm in 4th gear, which is way past the power peak of a 14b. If I was going to go faster, I'd need to find more top end power. Except I'm still using stock 450cc injectors, stock smic, stock IC pipes, stock intake manifold, and stock cams. Plus I have more weight in the car from adding a scattershield and 4 point roll bar, which was needed because I ran a few tens last year.
Special thanks to Sean at FFtec.com for fabing a first class rollbar, and for making it out of cromoly so it doesn't weigh too much. It has some sweet welds, too. I'm proud to pop the hatch and show it off.
Here's how the build went. I bumped the compression up to 9.0:1, last time I had 8.3. I also got a crank scraper and adjustable cam gears to (hopefully) dial in more top end.
The tranny was upgraded with an evo3 first gear which is taller and lets me go a few mph faster in 1st, I also got double syncros on 2,3 and 4th gear. I saved 2 pounds with a PTT twin disc clutch, vs the fidanza/ACT combo I had last time. This should speed up the shifts.
A new wheel/tire combo saves 6 pounds per corner. 15x7 Rota Slipstreams with 225/50x15 BFG Drag Radials. These tires are 23.9" diameter, which reduces the effective gearing. Essentially, this size tire makes all the gears slightly shorter while being lighter and offering better traction than my previous tires (Kumho MX 225/50x16.)
For boost control I shimmed the wastegate with a 3mm washer, and wrote some code in my eprom to use the EGR solenoid as an on/off switch for the air that goes to the MBC. So it's an E-MBC. How it works is when I go WOT the solenoid closes at 5600 rpm, which shuts off pressure to the MBC. At that point it's like running with the wastegate line disconnected, but it still allows the MBC to control boost below 5600rpm.
I also had a plan to tie it all together. It goes something like this: raise the stutterbox to 7k and launch that f'ker hard!
OK so a 7k launch didn't quite work out. I found that 6250rpm was just about right. On one of tonights runs I pulled a personal best 1.57 60' time. That felt really good. I'm sure I could do better with a hot, sticky track. (hello Sacramento)
At tonights race I had 4 good runs back to back. First I ran 11.91 @ 112 to beat my old 14b time of 11.98. I was happy with that.
Second run was an amazing 11.69 with a 1.57 60'. I was very happy with that!
3rd run was 11.67 @113.71. I'm knocking on Leons door.
4th run saw cooler airtemps and cooler track temps. I spun hard all the way through first gear, which reduced my ET, but the cool air helped the trap speed. 11.709 @ 115.05mph.
Here's a link to the timeslips for the 3rd and 4th run 11.67 On A 14b! - Timeslip of two runs, 11.67@113 and 11.7 @115 DSMtuners Gallery
I also took 2 in-car vids that I'll post up tomorow.
Exactly two weeks ago I finished rebuilding my motor, head, and tranny. So I figured, why not try for some fast times on the 14b again? Here's what happened last time, www.dsmtuners.com/forums/drag-strip/236131-11-second-14b.html?
This time my goal is to go faster than 11.64 on a 14b.
After all I did to the car last time, where would I get that much more speed/power? I already crossed the line at 6300rpm in 4th gear, which is way past the power peak of a 14b. If I was going to go faster, I'd need to find more top end power. Except I'm still using stock 450cc injectors, stock smic, stock IC pipes, stock intake manifold, and stock cams. Plus I have more weight in the car from adding a scattershield and 4 point roll bar, which was needed because I ran a few tens last year.
Special thanks to Sean at FFtec.com for fabing a first class rollbar, and for making it out of cromoly so it doesn't weigh too much. It has some sweet welds, too. I'm proud to pop the hatch and show it off.
Here's how the build went. I bumped the compression up to 9.0:1, last time I had 8.3. I also got a crank scraper and adjustable cam gears to (hopefully) dial in more top end.
The tranny was upgraded with an evo3 first gear which is taller and lets me go a few mph faster in 1st, I also got double syncros on 2,3 and 4th gear. I saved 2 pounds with a PTT twin disc clutch, vs the fidanza/ACT combo I had last time. This should speed up the shifts.
A new wheel/tire combo saves 6 pounds per corner. 15x7 Rota Slipstreams with 225/50x15 BFG Drag Radials. These tires are 23.9" diameter, which reduces the effective gearing. Essentially, this size tire makes all the gears slightly shorter while being lighter and offering better traction than my previous tires (Kumho MX 225/50x16.)
For boost control I shimmed the wastegate with a 3mm washer, and wrote some code in my eprom to use the EGR solenoid as an on/off switch for the air that goes to the MBC. So it's an E-MBC. How it works is when I go WOT the solenoid closes at 5600 rpm, which shuts off pressure to the MBC. At that point it's like running with the wastegate line disconnected, but it still allows the MBC to control boost below 5600rpm.
I also had a plan to tie it all together. It goes something like this: raise the stutterbox to 7k and launch that f'ker hard!
OK so a 7k launch didn't quite work out. I found that 6250rpm was just about right. On one of tonights runs I pulled a personal best 1.57 60' time. That felt really good. I'm sure I could do better with a hot, sticky track. (hello Sacramento)
At tonights race I had 4 good runs back to back. First I ran 11.91 @ 112 to beat my old 14b time of 11.98. I was happy with that.
Second run was an amazing 11.69 with a 1.57 60'. I was very happy with that!
3rd run was 11.67 @113.71. I'm knocking on Leons door.
4th run saw cooler airtemps and cooler track temps. I spun hard all the way through first gear, which reduced my ET, but the cool air helped the trap speed. 11.709 @ 115.05mph.
Here's a link to the timeslips for the 3rd and 4th run 11.67 On A 14b! - Timeslip of two runs, 11.67@113 and 11.7 @115 DSMtuners Gallery
I also took 2 in-car vids that I'll post up tomorow.