Since no one mentioned it, the turbo intake pipe helps as well. Anything that can reduce the vacuum pre-turbo helps. That's why running speed density and removing the maf and adding a smooth pipe is good.

 

Yeah that caused all kinds of headaches for me when I put on my HKS suction pipe. It changes the MAF readings like crazy. I think it is because the pipe tapers.

I suppose SD is in my future.

I've read that people have removed the MAF honeycomb with pretty good results. Understandably they had to completely re-scale the MAF. Doing this would reduce pre-turbo restrictions.

On that note, filter selection makes a difference too. I noticed going from a K&N small cone to a large cone that I was able to hold more power up top. Then going from the large cone to a vibrant filter with the internal cone, boost response vastly improved.

 

Yeah, I have a 4" Dejon intake and some huge Amsoil filter (9" or something) waiting to go on with SD. It's just too cold to work on my car. I've been waiting ever since the SD jitter fix was established.

 

So we have determined that we want the least amount of pressure reduction before the turbo inlet and the least amount of back pressure after the turbo exhaust outlet.

What about exhaust manifold designs that affect turbo spool?

 

I forgot to mention this, but having colder air helped my low end a lot. I'm running an APS cold air extension with a huge air filter. I can't say how much it helped, but with the improved low end torque, I can lay into the throttle and it's almost like driving the turbo spool with my foot.

Here's a link to a member of NorcalEvo who also is running a very similar setup. Made the most power on GST Motorsports Mustang on our **** 91 octane.
http://www.norcalevo.net/showthread.php?t=32921

 

Jarrod Hoops tested, on his SM race car, various tubular ones and couldn't find anything that spools faster than a ported/coated stock one.

d

 

Guess that is good for me...I have a ported and polished stock exhaust manifold.

 

Not coated, though. Remember anything that maximized temp or pressure pre-turbine and/or minimizes temp/pressure post turbine will help with spool. Anything coated pre turbine is good and post-turbine is bad, at least for spool and turbine efficiency.

 

removing the honeycomb in the MAF never required me to rescale. go SD it makes a difference!

maybe not related but recheck ur mechanical system and raise WG spring pressure.

 

I've got a whole roll of header wrap and a can of silicon sealing spray sitting under my work bench. I'll add that to my to do list this winter. I may even invest in a hotside wrap even though my hotside is already ceramic coated. As is my 02 housing.

 

The HKS intake cause irratic maf readings because of being so smooth. The factory intake pipe is acordian style. Also not as prone to heat soak.

Swain coat is the way to go in the long run. Wrap will cause the metal to get weak and crack in time.

The smaller pipes and stock ic will be the best for response. Big ic and ic piping will make more power up top. Look at any dyno graph with logged boost and you will see tq is almost always directly effected and a mirror image of your boost. More boost = more tq (most of the time)

Evan Smith

 

The intake pipe plays a major role in spool-up, response, and upper rpm power levels since it is the first point of entry for the air being used by the motor to convert to energy.

While modding your cars, keep in mind that the engine is in essence nothing more than a glorified air pump. Getting the air in and out as quickly as possible is always the goal.

Hope this helps.

 

Hi, I wana ask you what kind of gains were achieved with porting and polishing the stock exhaust manifold?

regards
NAB

 

sorry double post.

 

well i have a jdm 8mr and with a ported and coated stock manifold i was spooling about 130-150rpm earlier (ie XX rpm to get 15PSI) in 3rd gear. and i could put one or two degrees more on the same map.... that is with stock turbo and dump pipe (o2 elbow)