I own a JDM MY01 STI Bugeye.
I've arranged to have Bob Rawle re-map the car but will wait to fit a complete 3" de-cat exhaust, Walbra 255 pump, and HKS panel filter just before the map.(Pump and filter already fitted)
I'm hopefully picking up some Unequal quality copies of Gruppe-S headers with up-pipe this weekend.
I will lag the turbo downpipe and whole of the headers and up-pipe.

I have two questions, main one is what difference will the headers make as regards BHP/Torque/Spool up after mapping.
Secondly, what BHP and Torque do you think the car will produce as an average after the re-map.
I did ask Bob, but hadn't intended on the headers then

 

Come on! You have to prioritise your work you know

 

I SAID!!!!!!!

 

*cough* try drivetrain.... */cough*

 

 

Depending on type & style, you will generally increase torque and increase spooling by about 200/300rpm.

 

My God a reply!!!

Cheers Gaz

 

I went through all this and then some about 3 years ago looking for 360 bhp.

The headers will give a gain in the mid range, but certainly will open up at the top of the rev range.

You will suffer a little at the bottom.

They are really good when working with complimentary mods.

 

Nice pic 911. any idea how much wrap you used?
Jamie

 

It was a long time ago it seems!
About 40 feet or more as I did the down pipe too. The headers took ages.

 

I would rather go for Tomei headers over the Gruppe S ones.

EJ20 NEW RELEASE INFORMATION

They will be what I'm going to fit to my Spec C in the near future.

Have you considered getting the headers ceramic coated rather than heat wrapped?

 

There's a technical section of the forum called "drivetrain" ...

TX.

 

Exhaust headders aren't really drivetrain. But it prob wants to be moved to the general technical

 

Coating would be the best solution as the wrapp does deteriorate over the years.

 

I also know of a few people who have had issues with wrapping. Not on Scoobs but on CTR's. A few guys I know fitted uprated Toda 4-2-1 manifolds and wrapped them, only for the wrapping to eventually end up holding water and causing the manifold to crack in places. Don't know if this could be an issue on Scoobs though.

 

Did I read somewhere that wrapping can cause the wrapped bits to get so hot it can cause damage? Feel free to call me an **** if it's applicable

TX.

 

This is where the quality of the headers themselves is important.

The idea is to keep the exhaust as hot as possible so it hits the turbo as fast as possible (cooling gasses slow down as they contract on cooling in a given space, ie the header pipe)
This means the steel getting/staying very hot. We have all seen cherry red and brighter turbo's, the headers get this way at hard full-chat running sessions.

The stainless steel and the welding come under high stress and especially the way the headers are formed. If too stretched, the tube wall thickness is greatly reduced and after welding/heating the area is stressed further. This will lead to cracking locally and then a full tear.
This will happen with the coating too as you are trying to do the very same with it as the cheaper wrapping does.

Imprezas wrapped are very prone to wetting of the wrap due to where the headers pass on the bottom of the engine.

Graham.

 

In the grand scheme of things does it really make alot of difference if the headers are wrapped or not?
I've already done the de-cat down pipe but wondering if it's really worth wrapping stainless headers?

 

imho:
Yes.
Un wrapped the heat radiated off them will do for the wiring close by, the sump and the oil filter will get a roasting and as heat rises, at traffic standstill the heat will soar in the engine area heating the TMIC and a bit more on the way up.

Heat Management sound a bit fancy, but that is what you are doing, not just hitting the turbo harder/better.

Graham.

 

I noticed a difference in the heat when i opened the bonnet after i had my headers wrapped (Harvey Smith specials )

 

Cheers folks