Underdrive Pulley Questions

[Ghostrider 310]

+1 on cover fitment, it is also a good idea to get some flexible heat shield and cover the line that runs very close to the header to protect it from failure. I can't remember whether it is a PS lines or radiator line but you'll see it, I think it's a PS line. JC Whitney makes a corrugated heat shield sleeve that is perfect for the job.

[Meir]

Originally Posted by Steve Tinker

Meir
Just to put your mind at rest, I fitted a set of Chinese sourced headers (from Delubois Parts) onto my 2001 S. No other mods mechanically. The fitting went well, bolted strait on to the heads & secondary cats with no drama's. There is definately no loss in mid range, and the balanced length header pipes really come into their own at 4,000 rpm. In fact, as far as I am concerned there are no downsides apart from not being able to fit the rear plastic undertray.
One difference for you though is that here in Australia we don't have cats in the header - this may or may not have an impact on US cars.
The headers worked so well that I bought the cat delete test pipes from Delubois, and bolted them onto my stock rear muffler. This combo gives a really good sound above 4,000 rpm without the dreaded drone.

thanks Steve.
couple of reasons for asking:
1. i have the test pipes installed, and right away noticed a drop in torque in the low RPM. no doubt that once the engine gets to 3k RPM and up, there is extra gain.
2.the plan is going totally catless. got headers waiting to be installed, and once i finish my "winter project", i'm gonna start with my home made PSE (got most of the needed parts in hand)

since i don't track my car, i rather have more torque in the low mid then the high RPM.
BTW. as part of my project, the car is going back to stock, and then to the dyno.
next:headers, test pips,open muffler, large TB and plenum,UDP, ECU flush and dyno again.
its about time someone will show the real numbers. it might as well be me.

[Ghostrider 310]

Do more research Meir, there are many who have written that a Boxster needs a certain amount of back pressure. One would think less restriction is more power always but in this car it may not actually be true. You also may get jammed up at inspection time assuming Fla has such a money maker.

[Meir]

Originally Posted by Ghostrider 310

Do more research Meir, there are many who have written that a Boxster needs a certain amount of back pressure. One would think less restriction is more power always but in this car it may not actually be true. You also may get jammed up at inspection time assuming Fla has such a money maker.

That is exactly what I'm talking about. I know some back pressur is needed. that's why I'm surprised to read that some of you guys are running headers and test pipe without experiencing any loss of torque.
I defenetly plan to read as much as I can about the subject.
Just to give you the general idea, the muffler will be bypassed (partly) by valves.
The valves will be controlled by an on off switch and/ or by RPM, using a special module.
We kind of hijacked this tread, so when I'll start working on it, I'll start a new one.
I hope to receive a lot of opinions and ideas.
And no. No inspection In FL. you can ride a car with a jet engine if you want

[Ghostrider 310]

Just another reason to hate NY, it's a laugh taking your one year old truck in with 7 thousand on the clock whilst a technician pretends to make sure it's safe, state money grab NY is great at that kind of stuff.

My 986 still had the cats as that year they were placed downstream of the header pipe. What I'm saying is the addition of sport muffler & headers left the catylytic converters in place. Maybe they provided the back pressure that made the system retain the low end torque, can't say for sure. All I know is the headers, UP, sport exhaust and intake mods did improve the derriere dyno.