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Discussion Starter #1 (Edited)
I'm trying to not make this post a novel, but here's the deal...

I have a GT28R on a cast mani that I'm going to keep for next season too. I'm really enjoy the turbo, but a part of this game is to make things better, right? So I'm looking at ways to improve my setup without changing the turbo. If I decide to change turbo later down the road, I will benefit from the things I do now anyway. FTR, the car is used for aX and hpde's, no drag racing, thats why I went with a small turbo in the first place ;)

The turbo sits at 15psi, and upping the boost didnt made more power in the lower rpm's, but did nothing to the upper revs, so I think 15psi is right where it like to be at least right now. Here's the setup:

D16Z6
fjt i-beams and vitara's
Stock head, but crower springs
Cast mani
Gt28R
3" DP, 2.5" exhaust
Ported z6 IM and I think 63mm tb
~240 whp @ 15 psi on a mustang dyno

The stuff I am thinking of doing:

Compression. The vitara's on the i-beams gives me 8.37-1. I need to check the piston to valve clearance once I have decided what cam to use, but milling 0.06" will give me 9.4-1, so I will do that if possible. Cant really see any reason not to do it besides I might need to use a shorter t-belt. If the -11cc vitara piston is made during the winter, I might try that out too, giving me a nice 10.2-1 ratio :)

Head. If the bisi group buy goes through I will have a 2.4 turbo cam. I'm also considering getting a port job on my head. I dont know enough about whats happening inside an engine to be sure, (and its difficult to type out what I really mean :p ), but I'm not sure if I will benefit from this kind of mods, since the output is pretty limited to what the small snail can push anyway. I'd really like some input here...

Exhaust. I'm at ~240whp now. I'm running 3" Downpipe into a 2.5" exhaust with a straight through resonator and muffler. Will I gain anything if I make it 3" all the way? I need the car to be relatively silent (below 90dB) to ba able to make it past inspection on some hpde's.

E85? Not sure about this one... As far as I know, E85 give you good gains when you are running high boost/high hp and the fuel is the limit for how much ignition you can run. So I should not see any gains from it...?

Anything else I should consider looking at?

Thanks in advance
 

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Head work would seem to be a great idea. As far as the exhaust just disconnect it where it gets smaller and do a pull, if the AFR goes leaner, then the 2.5 exhaust is a restriction. I would also consider modifying that manifold for an external wastegate with open dump if it will pass inspection.
 

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head work for sure. Get a good port job, maybe a 3angle if you can as well. And the bisi cam and gear.

-Luke
 

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Port work and Ram horn manifold...
or even maybe a mini-ram for quicker spooling. depends on how bad his cast mani looks.

OP- if you know anyone good you can also have them port the turbo housings for better efficiency.

-Luke
 

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project lowball made 480whp on a stock y8 head port and stock y8 cam.

i think you are better off doing a free flowing exhaust and getting a retune. maybe running higher octane fuel.
 

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project lowball made 480whp on a stock y8 head port and stock y8 cam.

i think you are better off doing a free flowing exhaust and getting a retune. maybe running higher octane fuel.
i don't follow his thread but at what RPM and on what turbo. This guy said he runs autox, so i'm guessing lowballs build is the OPPOSITE of what the OP is working for. :yes: You want to shove as much air through this build as you can to keep that turbo constantly spooling

-Luke
 

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Classic Man
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i don't follow his thread but at what RPM and on what turbo. This guy said he runs autox, so i'm guessing lowballs build is the OPPOSITE of what the OP is working for. :yes: You want to shove as much air through this build as you can to keep that turbo constantly spooling

-Luke

7200rpm on a 50 trim t3/t4.

lets just put it this way.... his head is not the problem right now. for what ever reason hes not making power over 15psi. get that resolved. chances are the exhaust is the problem.

the head can flow way more CFM than its being asked of at the moment.
 

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mini ram or a tubular manifold.. port work, cam (bisi 3.6 or 2.4) and valve springs.. definitely would free up some power.

how big is the current exhaust? its all about 3 inch :)
 

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i like to mod in the best dollar / hp ratio possible

a 3" exhaust, maganflow muffler(is 100% stright through) and a magnaflow resonator will make the car quiet when cruising and will flow like stright 3" when you get on it. this I think would be the best option for more power all across the board and would cost you 250-350 if you know where to shop :D

as far as changing the mnifold i find that to be a bad idea, you would need to possibly mod your DP, charge pipes, and oil return. if you want to better the cast manifold a few hours spend porting and ceramic coating (about 75-100 around my area) will help a bit more with efficiency get the inside of the mani coated too so it will hold the heat and energy into the turbo!

after that its all $$$$$$$$$$$$$ mods

ive seen your vids and your car is cool as hell hope this helps but i think the exhaust is the biggest stop at the moment

also its a mustang dyno so your problly arounf 275ish on a jet
 

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Discussion Starter #12 (Edited)
Well, I have been considering changing manifold and external manifold a lot of times, but I just keep ending up staying with this cast. Reason is space and heat. I need to have space for a thick fullsize radiator and a heat shield between to keep the watertemp down during 30 minute sessions. A miniram would be very difficult if you look at how the wastegate needs to be, and I think I will see problems with a fullram because there will be a lot of red hot piping really close to the radiator, and I am really, really sick of dealing with overheating problems. A log could be used, but I honestly think this cast flows better.

If there was a manifold that outflowed the cast, had a good wg placement that made it possible to reroute the dumptube into the dp all for a decent price I would be all over it. But I dont think there is one.

The setup:




7200rpm on a 50 trim t3/t4.

lets just put it this way.... his head is not the problem right now. for what ever reason hes not making power over 15psi. get that resolved. chances are the exhaust is the problem.

the head can flow way more CFM than its being asked of at the moment.
Not sure what excactly is the bottleneck, but I am afraid it is the turbo. So I'm also thinking that maybe cam and headwork wont help me much. Not sure about the theory behind all this, thats why I started this thread. :) The bisi cam however will be here if the group buy goes through, and I wont let it sit in the box.

I've seen several graphs with power near and even above 300 whp in the nissan forums. They are using a 1.8 engine, but I want to try if its possible to get closer to 300 by making the setup more efficient. If I get power hungry I'll just have to get another turbo, but that means lots of cash, work and slower responce. Its not like I NEED moar power, but I like the challenge.

The graph from the last time on the dyno with the stock cam looks like this:



Later I tried out the crower stg2 on a mustang dyno and made the same peak power, but with a torque loss all the way up to 5500rpm. I know I can compare 2 dyno's, but I have gps logs from the track I usually go to, and the crower cam were slower on the straights, so i'm back to stock again now.



how big is the current exhaust? its all about 3 inch :)
Its 2.5. Kind of regretting that I didnt choose 3" when I made it together a couple years ago :p

i like to mod in the best dollar / hp ratio possible

a 3" exhaust, maganflow muffler(is 100% stright through) and a magnaflow resonator will make the car quiet when cruising and will flow like stright 3" when you get on it. this I think would be the best option for more power all across the board and would cost you 250-350 if you know where to shop :D

as far as changing the mnifold i find that to be a bad idea, you would need to possibly mod your DP, charge pipes, and oil return. if you want to better the cast manifold a few hours spend porting and ceramic coating (about 75-100 around my area) will help a bit more with efficiency get the inside of the mani coated too so it will hold the heat and energy into the turbo!

after that its all $$$$$$$$$$$$$ mods

ive seen your vids and your car is cool as hell hope this helps but i think the exhaust is the biggest stop at the moment

also its a mustang dyno so your problly arounf 275ish on a jet

Yeah, I like the way you are thinking, and it wont cost me much $ to weld up a new exhaust. I'll go ahead and try to disconnect the exhaust and see what happens to the afr. The manifold were ported when I installed it, along with the turbine inlet (to make them match perfect, the chinese has made the outlet from the manifold bigger than the turbine inlet). And thanks!
 

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the turbo is pleanty big enough for more power IMO look at the compressor maps should be able to flow enough no problem

this manifold is kindof a cast-miniram in a way
HONDA CIVIC T3 CAST IRON TURBO MANIFOLD D D15 D16 CRX : eBay Motors (item 270616867469 end time Aug-09-10 19:59:36 PDT)

this ideam might be a bit more work but sould redo the intake for the turbo to grab some cooler air?

see where your charge pipe is right now? move it from there to inside of the bay and then run the intake down into the fender well, i went as far as to run pipe all the way to the front bumper(no there havent been issues with rain at all)
for a track car nice clean air at speed can be very very useful!

here is when i had it mocked up



finished up
 

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Discussion Starter #14
Havent seen that maifold before, is that a new product? But it looks like it puts the turbo pretty far forward? I'll be looking for pics of it installed in the future (as long as the car works, I wont be changing much before winter anyway, I just starting the thinking in good time ;) )

And about the intake I like the use of the stock air box, never seen that before! I'm sorry about the picture, its actually a little bit old, and I have already relocated the filter into the fender, but I like your solution much better :)

My current intake looks like shit now, and I need to clean the filter all the time because it sits so low :p





And I actually gained about 5km/h on the longest straigth on this mod :)
 

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hahah nice yeah it works when i did it i noticed a good bit more go with it

there is a memeber on here with that manifold I think im just gonna order it to test how it works out

but honestly i think the exhaust is your best bet for gaining power /$

looks like you have a pretty good setup over all though, could go to home depot or other home improvement and pick up some air duct insulation tape its aluminized and wrap the charge pipes, looks like they are mild steel so im sure the just soak up heat from the engine bay, i know mine do


i doubt a bigger fmic would gain much if anything and just bump the lag on the throttle response

OOOOO one big thing i noticed is where the source for your EBC!!! its hooked up to the turbo/hot pipe! change it over to the cold pipe after the intercooler :D will "send" the correct signal to the ebc since the intercooler drops a bit of pressure

plus the shorter vac lines will help it build boost a bit quicker
 

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also get an OEM oil cooler :D

help you stay out on the track longer

 

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Discussion Starter #17
hahah nice yeah it works when i did it i noticed a good bit more go with it

there is a memeber on here with that manifold I think im just gonna order it to test how it works out
Interesting, let me know how it works out!

Oh, and the ebc and oil cooler already fixed, I should stop posting old pics, lol. I couldnt fin an oem cooler over here, but I have an aftermarked in the fromt squeeses between the ic and radiator which works great.




Any thoughts around E85 and compression?
 

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Discussion Starter #19
You don't need E85 until you get into silly compression with the turbo.

Is your cam timing correct?
Thats what I have heard from the last guys I've talked also. Guess thats good news, no need to upgrade injectors :)

Not 100% sure about the cam timing, as I dont have the specs to get the stocker degreed. But it shouldnt be too far off considering my head has only been decked once, and it wasnt warped at all then. I have played a little with the cam gear and the fuel graphs keeps shifting around, but the gps logs I got from the track says about the same speed on the straight anyway...
 

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If you want to upgrade the cam can get a stock cam reveling deltas 272 cam is 152 if you say your from d-series and you can keep stock valve train

I agree on e85 not from personal exp but just what I've read no pumps up here :(

The cr bump is always a good idea only issue shaving that much is you'll need an adjustable cam gear to get the timing straight on, mutt more cr is always a good thing if the fuel can handle it. Plus your 9.4 you stated isn't to high at all and I'm sure will net some power all over the place
 
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