dchung1

I just removed my stock header.. btw i have a 5th gen base prelude 2001.

and i noticed the dc header opening diameter is 42 mm approx.. and the engine block opening is 35mm where the dc A pipe connects to.. so my question is do you guys think I would get any benefit matching the engine opening to the dc header opening by dremeling it out a little of course carefully.

has anyone done anything like this

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2001 base 5 speed, vafc tuned,aem CAI with air ram, AEM pulley, apexi ws, msd 6A , DC CC headers, car sound 2.5 cat, coolant bypass, egr bypass, ob2 workaround, no back seat, tein ss, nuespeed strut, progress rear sway.

NXLude

I would be too scared of getting metal shavings in the cylinder....to get gains you would have to go deep in there and take a afair amount of material out....you would need hella built engine too see much gain

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H22 DC2 in the works

achemze

I dont think built engine is the secret to finding horsepower from that. I think its tuning and total exhaust flow. If you ran around boosted, you'd probably notice it. But not so much n/a. Besides, arent the dc headers pretty much engineered to work the way they are. Its like modding a type-r, your trying to out engineer the manufactor.

I think you wont see any noticable gains for the amount of work it would require. Plus, you'd throw off the dynamics of the air travel ... and you'd need to polish it when you were done.

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2001 Honda Prelude Type-SH
2001 Honda VFR800FI Interceptor

PROSTREETONLINE == DONT BUY LIST

RJs99TypeSH

From what I understand, your plan is to dremel the exhaust outlets on the head of your motor so that they match the DC?

Don't do it. Although not as sensitive as the intake ports, screwing up the curvature and flow characteristics of the exhaust ports on a motor can be extremely detrimental to performance. A poorly ported/polished head can drop horsepower in a huge way from the factory layout, and even cause unfavorable engine reliability issues.

If you want your head port/polished have it done professionally; even if you do it and your car still starts and seems to run ok, you'll eventually regret it. You really only get one chance at a good port/polish; especially if you plan to take as much material away as you are talking about (7+ mm).

R.J.

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Be vewy vewy quiet...