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Discussion Starter · #1 ·
Hi guys
Here’s my setup and i dont know what move should i take considering more power, what are my limiting factors?
I want to change my exhaust to a full 3”
And raise my boost to somewhere between the 21-23psi range.
What would be my next limiting factor?
The setup:
100oct
D15b2
H mxr rods
Vitaras
Stock z6 head, home ported
Stock z6 manifold and tb
Siemens deka 670ccm/3bar
Walbro 255lph
Mxr gt2871 currently on 17psi(1.2bar)
2.25ic piping
Stock ignition
2.25dp
Stockish exhaust, no cat 1.75” :/
Tuned on hts
now its around 230hp
 

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4d EG manual rack/trans low n slow
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282 Posts
Well, turning up the pressure will give you power, until you max out the turbo...
Is this a track only car, or do you drive it on the street?
Personally I'd upgrade to external coil or DIS if you're able, I don't think you can have too good of a spark..
Are your power numbers from a Dyno tuner?
 

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93 Civic HB SI, 95 Civic HB CX
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2,406 Posts
What is your current injector duty cycle at full throttle and max power?

If you're over 70% duty, get and install a 1:1 rising rate fuel pressure regulator.

Then, get and install a turbo specific cam to reduce valve overlap in VTEC. Nothing too wild on cam lift, unless you want to upgrade springs and retainers as well. Keep redline the same.

Easy 50-60+ whp doing nothing else mechanical to the car, even with boost kept the same.

With the stock cam, you're literally blowing boost out the tailpipe because of the overlap in VTEC, you'll significantly improve volumetric efficiency with the cam upgrade.

You'll need to have it retuned after upgrading either the FPR and/or the cam.
  • Adding 1:1 FPR by itself without a retune will cause you to run very rich in boost.
  • Adding cam without installing the 1:1 FPR, and without a retune, will cause you to run very lean in boost.

Its more of a weekend warrior.
Is my ignition the thing that would stop me making more power?
No thats a guesstimate according to 100-200kmh in 15s
If you did the cam and FPR upgrade I suggested, you'll likely need to gap your plugs a bit tighter, and maybe go a bit colder on the heat range, but no, your distributor ignition system should do fine.
 

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4d EG manual rack/trans low n slow
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I would suggest a Dyno tune to see where you are, I'm street tuned (mostly) on HTS and I'm sure a Dyno tune would help, and show you where your power band is. The other suggestions are also good IMHO
 

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Discussion Starter · #6 ·
Thanks for your replies!
Im around 55-58%inj duty cycle, would a fpr still help?
What cam would you recommend?
I didnt find any cheapish cams
I was looking at 59300s, but i want it to be done next year with springs and retainers and going a bit over 8k.
Now im stuck at 7k, but after the exhaust and upping up the boost i want a street tune revving to ~7500
Do you still have other recommendations for power?😀
 

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You have a tiny downpipe and exhaust.

Build a megaphone 3.5" downpipe that narrows to 2.5" full exhaust. No need for 3" piping. You wont really gain much for power.


You WANT a large downpipe initially to let the turbo breathe, then reduce down to maintain velocity.

The civic chassis really does not support 3" exhaust piping unless you oval it out in some spots, or are willing to allow it hanging low.
 

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Discussion Starter · #9 ·
Thats the next thing on the list :D
Im still having a hard time finding 3inch pipes, dont even think about 3.5”.
But ive seen loads of civics with 3” full exhausts.(?)
 

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BATSLOMAN GIVES NO FUCKS.
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Discussion Starter · #16 ·
My bad, i am looking for pipes under 80$ that i can weld and can be shipped under 10$ to Hungary😀, but its getting there so im focusing on the next step as my title says
 

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Buy a short length of 4" steel piping, cut slits on one end and narrow it down to the turbo. Do the same thing with the other side to 2.5" exhaust.

The equivalent of $80 USD is not going to get you anything of good quality that bolts up.
 

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Sloppy Jalopy
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Then, get and install a turbo specific cam to reduce valve overlap in VTEC. Nothing too wild on cam lift, unless you want to upgrade springs and retainers as well. Keep redline the same.
Then, get and introduce a super unambiguous cam to lessen valve cross-over in VTEC. Not really wild on cam lift, except if you need to overhaul springs and retainers also. Keep redline something very similar.

hmmm
 
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