Brad's DC2 GSR Tragedy

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Scavenging effect only happens up to the collector of the header and a little bit after. Anything after that is a restriction.
 
Keep the GSR head. No sense in getting a B16 head only to drop your compression ratio. Stick with the GSR head, throw some P30 pistons in that bitch with some cams and you might hit that 200whp.

This^
 
I say run 3" no cat, use a 22" long resonator and magnaflow muffler. Mine sounds great and YOU WILL PICK UP HP WITH 3" over a 2.5".
MVI_5348.AVI - YouTube

Also,
Keep the GSR head. No sense in getting a B16 head only to drop your compression ratio. Stick with the GSR head, throw some P30 pistons in that bitch with some cams and you might hit that 200whp.

Idling isn't good enough haha. I liked your exhaust from the first time I saw it in your thread.

I have a chance to get a 2.5" axle back Apexi WS2 muffler (for an Integra) from a mutual friend, although it needs a polish. I'll inquire about price then make my decision.

Its a big discrepancy online about the B16 vs GSR head. Some say the B16 head flows better, then others say the combustion chambers on the GSR head lower detonation and let you make more compression & power. I'm stuck now. :(
 
More compression would make you more susceptible to detonation, but you can make more power (GSR head). The two heads flow well enough that the difference between the two is negligible.

Here you can see how the GSR (Right) combustion chamber differs giving you a higher compression ratio with a smaller chamber.

images
 
I get what you're saying but why would Honda put a B16 head on the same B18C block (with higher comp pistons of course) to make a Type R motor? I thought that way would be better cause it's basically a "R" motor after.
 
That B16 casting head on the TypeR also has some mild porting done. Which you would not get on a standard B16 head.
 
nice teg sir..just need to fill the trunk holes flush.instead of pluggin them lol,bout to be pickin up same year,model an color teg,but has ls-t,
 
That B16 casting head on the TypeR also has some mild porting done. Which you would not get on a standard B16 head.
Right, but it's still the same head casting. Not trying to be argumentative here lol.
nice teg sir..just need to fill the trunk holes flush.instead of pluggin them lol,bout to be pickin up same year,model an color teg,but has ls-t,
Well.....wing might go back on after all. GL with your car man.
 
Right, but it's still the same head casting. Not trying to be argumentative here lol.

You're not arguing, you're agreeing with me that it is the same casting. ;)

Stick with the GSR head for more compression. End of story.
 
i thought 3 inch was over kill with
a only slightly modded car. i thought you wanted
some back pressure and none with forced induction

This is a myth and completely untrue.

A very prevalent and at times hotly debated MYTH.There are others as well: Mention brakes, specifically rotors, porting, catylytic converters and power loss, manifold flow (basic fliud dynamics and laminar flow properties and length -vs- RPM, "Q" of tuning) and so on......Too many times people will post and argue only what they have read and not what they have done firsthand.
 
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You're not arguing, you're agreeing with me that it is the same casting. ;)

Stick with the GSR head for more compression. End of story.
The compression calculator came up with 11.53:1 after P30 pistons. I'm fine with that.
A very prevalent and at times hotly debeter MYTH.There are others as well: Mention brakes, specifically rotors, porting, catylytic converters and power loss, manifold flow (basic fliud dynamics and laminar flow properties and length -vs- RPM, "Q" of tuning) and so on......Too many times people will post and argue only what they have read and not what they have done firsthand.
Too many variables man...:mellow:
Hey Brad, this thread and project/build is begining to have overtones of EPIC.
Thats what I aim for. ;)
well what i have learned first hand is that,
turboed with open DP pulled harder, and
on my 90 integra we gutted the cat and
removed the muffler to install a magnaflo ( i was 15)
and so with no cat or muffler we decided to
drive it and mess around and it was noticably slower.

but no dyno to prove this so thats that.

low end, slower.. top end, faster

Civ & EG I can agree with both of you. Open header N/A is slow as hell at first but screams up top. With my straight pipe on the CRX I lost bottom end but the thing would pull hardd till the limiter bounced.
 
Maybe below 3k you lose power?? I don't know, the dyno didn't even start reading that low.

Here is my car switching from JDM DC 4-1 w/2.25" exh with test pipe to RMF Narrow rep header and 3" exh. No losses. I think i post this same graph and these same words too many times.. :p

15357d1304012242-honda2.25to3exhe85-medium-.jpg
 
Can I haz dat powerbandz plz? :shocked: So a 10 HP gain plus a bit of torque, I'm down! Now would a stock GSR motor with a descent intake+header take well to 3" until it's built?

I get to insure the teg tonight!
 
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Can I haz dat powerbandz plz? :shocked: So a 10 HP gain plus a bit of torque, I'm down! Now would a stock GSR motor with a descent intake+header take well to 3" until it's built?

I get to insure the teg tonight!

I believe it would. We also found a short ram 3.5" intake (red) does pretty good vs. my 3" CAI (blue). Here is that comparison.

15358d1304012242-hondashortvscoldintake-medium-.jpg
 
well what i have learned first hand is that,
turboed with open DP pulled harder, and
on my 90 integra we gutted the cat and
removed the muffler to install a magnaflo ( i was 15)
and so with no cat or muffler we decided to
drive it and mess around and it was noticably slower.

but no dyno to prove this so thats that.
I'm think I'm following the full trail here. :) Not suggesting your results don't stand on their own merit.

Case #1 we have a turbocharged and tuned engine with an open down pipe that obtained an increase in performance.

Case #2 a 1990 Integra gutted can and installed magnaflow muffler and drove it around after gutting cat and pulling muffler prior to installing Magnaflow and it was percieved to be noticeably slower.

Don't want to jack Brad's thread and start up a flame-a-thon debate - but, this is interesting and I've messed with tuning exhaust systems a little here and there.

Case #1 - as Brad noted there are far too many variables to really base a conclusion beyond that it ran better and supports the "Less Backpressure is better" theory. The difference would really depend upon the exhaust system on it and how much backpressure it had - evidently it did have plenty of backpressure and removing it didn't throw the tuning off too far. As a turbocharged engine will live in an environment and be tuned to operate with significant backpressure anyway.

Case #2 - I don't know how much an ECU can compensate for a change in the system, but would speculate they can't "Adjust" that far. I base this upon experience running different ECU's with different maps on the same engine and having significant differences in performance. Also, to running a correct ECU map and changing compression ratio (increase from 9.5:1 to 10:1) on a given engine and it moving towards the lean side of ok.

Significant changes to an exhaust system on a non-electronic controlled engine generally will almost always require a jetting change and sometimes more (midrange transition needle changes) to optimize performance. What I'm suggesting is a significant change in the reduction of backpressure from a stock exhaust system to something else, may throw the tuning so far out of whack that the ECU can't totally compensate for it - thus the performance loss. Not a direct function of the reduced back pressure, but of the overall system equilibrium being thrown off kilter. Probably a condition of a lean engine as caued by a significant redudtion in backpressure and the engine breathing better.

Too many variables at play in case #2 for me to make a conclusion beyond it just not running as well. With a tune or perhaps increase in fuel pressure at the rail, it may have ran better.

Just speculation here.
 
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