If Any Of You Could Help Me With Some Tips On My E

[leostunts]

If any of you could help me with some tips on my exhaust.

Lexus1993 SC400 with 132000 miles.

I left the 2 cats that are bolted to the factory headers and installed 2 straight pipes at 2.25 to the rear factory exhaust mufflers and thats all, pretty loud.

I removed the mid section cat and the 2 resignators.

K&N replacement air filter.

I went to the dragstrip last night and ran 10.355 in the 1/8th mile at 800ft above sea level 70.88 mph and my best in the 1/4 was 16.178 at 81.72 mph at a different track the next day at a very high altitude 2640ft. above sea level, even with the corrections maybe 15.80 or 15.70 .

and average 2.4 60ft.

I even removed the spare tire and 1/4 tank of gas 91 octane.

This car stock claims 15.2 or 15.4 in the 1/4 mile.

My max stall was I think 2000 rpm couldn't even burn rubber if I tried. I did do nice burnouts in the water box.

I believe I lost some bottom end torque from the exhaust setup?

I didn't get to test the car out in stock form.

Butt do you think because of the straight pipe and no cross over pipe would be the cause of this?

I do think theirs better mid and top end range.

And I did order a cross pipe 2.25 inch.

[cruznroadking]

Keep in mind that the engine does have 132k on it & won't run as well as if it had 50k. Also what's your reaction time & how do you come out of of the hole? Do you get a lot of tire spin. Loss of traction off the line is critical. What tires are you running? How high do you rev the engine before shifting? Just throwing some ideas out there to look for. Burnouts are good to heat up the tires for better traction, tire selection sometimes makes the biggest difference. Do you do burnouts before every run. Because the tires will cool down between runs. Also 15.7 or 15.8 sounds like a respectable time for a stock (I assume) 132k engine. Adding on a crossover won't hurt but in my experience at the track, off the line traction is the most important thing. You can be cranking out 500 H/P but if the car doesn't hook up at the line you're not going anywhere.

[leostunts]

Keep in mind that the engine does have 132k on it & won't run as well as if it had 50k.  Also what's your reaction time & how do you come out of of the hole?  Do you get a lot of tire spin. Loss of traction off the line is critical.  What tires are you running? How high do you rev the engine before shifting?  Just throwing some ideas out there to look for.  Burnouts are good to heat up the tires for better traction, tire selection sometimes makes the biggest difference.  Do you do burnouts before every run. Because the tires will cool down between runs. Also 15.7 or 15.8 sounds like a respectable time for a stock (I assume) 132k engine.  Adding on a crossover won't hurt but in my experience at the track, off the line traction is the most important thing.  You can be cranking out 500 H/P but if the car doesn't hook up at the line you're not going anywhere.

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My reactions are almost perfect .574,.520 average .500 perfect light.

I've been racing for years at tracks , so I know theres no issues there.

Traction- Yes I burn out in the water box all the time and no burnning out of the hole. Holding max stall , like I said before couldn't ever burn out of the hole if I tried.

I manually shifted at 5700-5800 rpm and some times it would bounce off the limiter once or twice. Not really a crisp shift , slight delay after I shift.

Auto- was maybe a 10th or so slower, with no risk of hitting the limiter.

What kind of times are you getting in stock or modded times?

p.s. correct on 1/4 mile times are 84-86 mph.

[leostunts]

Keep in mind that the engine does have 132k on it & won't run as well as if it had 50k.  Also what's your reaction time & how do you come out of of the hole?  Do you get a lot of tire spin. Loss of traction off the line is critical.  What tires are you running? How high do you rev the engine before shifting?  Just throwing some ideas out there to look for.  Burnouts are good to heat up the tires for better traction, tire selection sometimes makes the biggest difference.  Do you do burnouts before every run. Because the tires will cool down between runs. Also 15.7 or 15.8 sounds like a respectable time for a stock (I assume) 132k engine.  Adding on a crossover won't hurt but in my experience at the track, off the line traction is the most important thing.  You can be cranking out 500 H/P but if the car doesn't hook up at the line you're not going anywhere.

←

My reactions are almost perfect .574,.520 average .500 perfect light.

I've been racing for years at tracks , so I know theres no issues there.

Traction- Yes I burn out in the water box all the time and no burnning out of the hole. Holding max stall , like I said before couldn't ever burn out of the hole if I tried.

I manually shifted at 5700-5800 rpm and some times it would bounce off the limiter once or twice. Not really a crisp shift , slight delay after I shift.

Auto- was maybe a 10th or so slower, with no risk of hitting the limiter.

What kind of times are you getting in stock or modded times?

p.s. correct on 1/4 mile times are 84-86 mph.

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I found my answer.

Check this out to see the benifit of the crossover.

http://www.timskelton.com/valkyrie/tech/images/h_pipes.pdf

[cruznroadking]

Keep us posted on the ET's if you decide to run the crossover pipe.

[DomLee]

It is quite possible that you lost some bottom end torque. A lot of people, when adding more "power" seem to focus on peak horsepower rather than the lower and more useable horsepower and torque.

Keep in mind that the vehicle when new,...had 92 octane available, as opposed to the current 91. That and manufacturers have "test driver's" that drive vehicles in an attempt to squeeze the best performance times available, based on whatever category they are focusing on. They will experiment w/ different tire pressures (for example) in order to get the best performance times. Not only that, but from the factory...all of the components in the vehicle are new. Every bushing is doing it's job properly. All of the various belts, etc. are new, thereby no slack minimizing any lag in performance.

Don't expect to get the performance times that were posted in the brochure. That is usually a best case scenario. Your car is over 10 years old...you have to expect a decrease in performance.

[leostunts]

It is quite possible that you lost some bottom end torque.  A lot of people, when adding more "power" seem to focus on peak horsepower rather than the lower and more useable horsepower and torque. 

Keep in mind that the vehicle when new,...had 92 octane available, as opposed to the current 91.  That and manufacturers have "test driver's" that drive vehicles in an attempt to squeeze the best performance times available, based on whatever category they are focusing on.  They will experiment w/ different tire pressures (for example) in order to get the best performance times.  Not only that, but from the factory...all of the components in the vehicle are new.  Every bushing is doing it's job properly.  All of the various belts, etc.  are new, thereby no slack minimizing any lag in performance. 

Don't expect to get the performance times that were posted in the brochure.  That is usually a best case scenario.  Your car is over 10 years old...you have to expect a decrease in performance.

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I let you guys know ,next time I go out.