the down pipe welds here were unbelievable . They must hav blocked 25% of the airflow . Unlike the itr header, the pipes were welded inside and out it appears.



d

 

nice but that doesnt mess up the contact patch or intended airflow of the engine does it?

 

if you mean the header mating surfaces, no, the weld is in about 1/4" or more.

The intended airflow of the engine? i think the intent was structure and longevity over performance on this one.

The upper header portion outlets were slightly smaller in diameter, but only a millimeter or two. One side was slightly offset, so i ported them to line up the same, but kept the "stepped" design, in case they meant to do that.

d

 

did you tell any difference with it? i'm in the process of doing the same with mine

 

i'm not too sure going by the butt dyno. I thought it felt a little peppier, but that could easily have been the weather that day, too hard to tell.

I went to the track, tho, last sunday to see if i could see the difference. I had a bad headwind tho, so i ran worse 1/4 times. With only getting 3 runs in, my times AND mph by the 1/8th mile were some of my best, including one mph better than the run in my sig (with basically the same 60'), despite the strong headwind (compared to a slight tailwind from my 14.19 run in my sig).

By the 1/4 line my mph were 2 mph lower, no doubt due to the headwind. Other racers were running as much as 4 mph slower that day. So i'd like to think that indicates i'm making more hp now.

I'd like to try to crack 13's with this setup, but i'm itching for some itr cams soon.

d

 

what did you use to port it?

i cant seem to find my carbide bit

 

good job

 

i used a cheap die grinder on a good compressor and did both with one 60 grit cylinder shaped stone bit. I'm thinking it took 3/4 of a hour per side, so have some patience. I think those welds are diamond plated.

Don't even bother with a dremel .

d