I ve got a custom topmount similar to FR on b20/b16 setup with GT35R and planning to go for 3.5" or 4" downpipe, but damn, the space are very tight and I have clearance problem as i have thick alu rad and slim fan. Appreciate if anyone can share their 4" or 3.5" DP on your topmount setup... it ll give me some idea as I can find any real life sample to look on here in my country. It should help to give me some rough idea on the routing of the DP. Its in EG chassis btw. Thanks in advance.


Modified by EG6SiR-T at 9:35 PM 8/5/2008

 

Well, let me just give a screenshot of my engine so you guy can help me out.

 

cmmon guys, share with me your engine bay shot with your 4" or 3.5" DP....thanks

 

my old ls setup for ya.

this was was only a 3inch but u'll get the idea.

 

Can I ask a stupid question, why do you need 4”? Would 3” support your goals?
I see and hear of people making big numbers on 3”, it just seems people would like to follow a trend more than the functional need.

 

...here is a pic. of my EG turbo b20 vtec with FR t4 topmount and 4in. DP

 

well, ill be pushing the motor rev up till 9kplus so since im fabricating the DP, might as well go for either 3.5" or 4"...but if the space is still a concern, ill settled with 3" though...

Anymore top shots of the DP from anyone?

boostfeen, u have any top shot of the downpipe to see how close it is towards your rad and block? thanks

 

no one else with your shots?cmmon,help me up a bit here.i know there r tons of guys in states runnin on 3.5" n 4" dp..

 

I am struggling to see where you wastegate is going.....but if it is that little ragged over on the left in between cylinder 3 & 4.....good luck wit that. No where near a full-race style manifold. Not to mention you have a four bolt housing FTL. I dunno, but it sounds like start cutting and fitting is about your only option. Or contact the person that made that manifold and have them make you a dp.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG6SiR-T &raquo;</TD></TR><TR><TD CLASS="quote">no one else with your shots?cmmon,help me up a bit here.i know there r tons of guys in states runnin on 3.5" n 4" dp..</TD></TR></TABLE>

..It will be much easier to mount the motor in the Eng. bay with turbo and manifold first, then start figuring out what needs to be trimmed or notched. Im sure a 3in. DP is all you need.

 

regarding the DP on a top mount turbo app... i have a 3" and it deff. does support my hp needs, however im switching to a 3.5, or 4" because it makes for faster spool up, there is more room in a 4" for the turbo to spool, and as far as tight spaces, im going to rout it the same way as my 3" but in the tight areas like the clutch slave cylender and ground clearence under the oil pan, im going to squeez it in a bench vice just enough to fit

 

Blown90hatcH

yeah, the WG is between the 3rd n 4th cylinder, but that s just for mocked up purpose. Im trying to put it below the turbo either facing the front or side towards the PS. Just need to have an idea where does normally you guys route your 4" or even 3.5" DP thru via your rad and your clutch cylinder slave, so i have an idea to fabricate a custom DP. Thanks anyway..

 

boostfeen,

Yeah, but there a lot of theory saying that it ll makes the turbo spool faster with 3.5 or 4" DP. But in the end i guess it ll go down to "how tight" the space will be. Anyway, im just aiming for 400-450whp for the time being...no more than that..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG6SiR-T &raquo;</TD></TR><TR><TD CLASS="quote"> im just aiming for 400-450whp for the time being...no more than that..</TD></TR></TABLE>

*falls out of chair laughing*

ok seriously, you don't have a supra but if you insist you can make it fit, unless you have welding skills i fail to see why you are even troubling yourself with this, drop the damn car off at a reputable fab/exhaust shop and let them worry about it. And you can always mount your fan as a pusher to open up space.

 

blinx9900,

wut seems to be funny anyway? is it to high to aim at such power?

Anyway, thanks for the idea, i thought of that with the pusher fan, it ll help out a lot in terms of space. Actually its not me who is going to fabricate the DP, it ll be a friend of mine from an exhaust shop, however in my country not many have down such fabrication of DP on honda EG type body. So it ll help a lot if i can get shots of pics how u guys did it in the states so i can give an idea to the fabricator to fabricate similar DP...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG6SiR-T &raquo;</TD></TR><TR><TD CLASS="quote">blinx9900,

wut seems to be funny anyway? is it to high to aim at such power?
</TD></TR></TABLE>

no no, the power goal is fine and you should achieve it easily, its just that with that power goal a 3.5 or 4.0 is just not needed at all, 3" is good for 600whp. I'd say 3.5" is not a bad idea if your shooting for over 500 for sure and you want room to grow but 4" is just too much imo. I'm sure there might be some minor gains but no ground clearence.

 

iv herd of a very noticeable defference on turbo spool by going with a 3.5" of 4" dp just due to the fact that there is more room for the exhaust right at the turbo, my buddy has the same set up as me, a top mount with a t67 but he has a 4" and he hits full 17psi of boost at 5600 rpms mine w/ my 3" hits 18psi at 7000 big fifference..

 

One we did about a year ago for a topmount/GT30 setup in a CRX (D series)

Made it hug tight

 

 

PSI2HI

In pic2, did this DP touched the clutch cylinder slave, how did u bypass it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG6SiR-T &raquo;</TD></TR><TR><TD CLASS="quote">PSI2HI

In pic2, did this DP touched the clutch cylinder slave, how did u bypass it?</TD></TR></TABLE>

No it doesn't. On 4" downpipe we bring them out towards the pass side past the slave then back and under the pan.

 

great thanks!

 

my old 3"

 

 

sick pics