Restrictions I'm looking at with the stock 02 housing and an evo mani and 3" exhaust

[JPJ2007]

Hey guys, Yea Im a newb.

I come from the world of Hondas so I have some background with
Auto mechanics however the DSM world is an entire different playing field.

I have a 95 GSX
Stock everything aside from K&N filter

From my research it seems the evo mani flows 30% better than a stock gsx mani Ported

So I'm going to be picking up an evo mani
I am also going to be having a 3" exhaust from the o2 housing installed.
Unless I can simply replace the o2 housing with piping right off the turbo and
drill a bung for the o2.

Well Im going to have the evo mani, 3" exhaust right off the o2 hoursing,
Straight back no cat no resonator etc...

What Kind of restrictions will I be seeing with the stock o2 housing.
Is it going to be to the point that I should do the exhaust untill I have the o2 housing
bought?

Also running no cat is this going to affect the reading on the o2 sensor just behind the cat?

I dont have any type of testing, Ever where I live.
No emmisions, no testing Nothing. Ever.

Well I just wanted to ask and I hope to get some answers,

I have searched and perhaps I did not use the correct wording but I didnt
find anything on my answer.



Oh also, Running this upgrade without tuning would be a horrible thing correct?

Or would It be ok for about a month or two before I have time to buy dsm link
and get some money for my local awd dyno shop.


Thanks!

 

[Mr Peepers]

The stock 2g o2 housing, when ported, is a good piece. Even the ported 2g exhaust manifold flows well, correct me if I'm wrong but I believe people have gone 10's with it.

No, you can not just run a pipe off the turbo outlet and weld a bung to the pipe for o2, the internal wastegate that merges back into the exhaust within the o2 housing.

The rear o2 sensor is only there to see if the cat is doing its job and will not affect o2 readings in any way if the cat is removed. The CEL may turn on though.

The stock t25's exhaust housing is the bottleneck between the manifold and o2 housing.

Full 3" exhaust will definitely help, and is a good first bolt on that generally doesn't need to be tuned for, yet you should feel noticeable gains. You may experience boost spike or boost creep if the turbine housing and o2 housing are not ported.

 

[JPJ2007]

Ok thank you for the information.

The reason I asked about the pipe directly off of the turbo is due to
when searching I saw turbo back Exhausts,
However I now put 2 and 2 together and realize those are most likely for
an aftermarket turbo with an external Wastegate

I still plan on buying an evo manifold so I don't have to mess with porting.
Im going to think about spending the 200 on the o2 housing. Thats a bit much for
just the o2 housing for me at this time. I'll have to wait another pay check or two.

The shop is welding me a 3" from the o2 housing, to a 3" flex pipe and a 3" exhaust behind that. Right to a muffler of my choice in which I am still sourcing out.
For Only $200 total. I coudnt pass this up seeing other shops wanted 400.

I was going to do this myself, seeing as my grandpa has a metal shop
However It was going to cost me 100 for the 3" ID piping, and like 40 for the 3" flex
So I could just pay an extra 70 and have the shop do it for me.



I was told If I obtained the evo mani, and had a 3" o2,dp and exhuast I could see gains
upwards of 60hp. Perhaps they meant after some tuning. But if It is not 100%
mandatory that I tune after the exhuast bolt on I will wait untill I get ahold of the
piping and fmic, bov and the Nice IM Before I spend some hefty money on an awd
dyno tune and time.

 

[DGajre777]

I don't see a point in getting an EVO exhaust manifold unless your current one is cracked. I say this because the T25 as said before is a bottle neck. You'll see more gains if you port the T25 too.

If you do decide to get the EVO housing - there is a cheaper alternative called GT manifold, made by turbochargers.com. Last time I checked it was being sold for $160ish and is ported to a 7cm gasket.

Do you plan to stick with the T25 and then upgrade to the T28 later? Take a look at o2 housings at www.punishment-racing.com and after than you'll be fine with a 3" setup past the o2. You do know that your check engine light will probably come on without a cat - right?

 

[Mr Peepers]

The stock pieces will get you far, I highly suggest you look into porting. I also suggest taking a look at the 2g upgrade path on this site, because honestly an intake manifold isn't needed at all, and will most likely hurt performance at this point.
If you do get DSMlink I think the money on a dyno tune could be better spent elsewhere, but that's just me.
Either way you have a lot of research to do before you start buying parts.

Good luck and welcome to DSMs

 

[JPJ2007]

Ok thanks for the heads up.
I was thinking about upgrading the turbo however I dont want to do too much
as to need to begin building internals.
I'll wait on the evo mani,
Im searching but how do I g about porting the o2 housing, the same goes for the t25.

Yeah I understand I'll throw a cel with the cat removed,
However, is the o2 behind the cat ONLY to make sure the cat is working correctly?
Or will this actually affect the performance of my gsx.

Im guessing its only to make sure the cat is working correctly as the first o2 is just behind the turbo to moniter the readings.

Im asking becuase my Motor I swapped in from Japan on my integra has two o2 sensors
One for cyl 1+3 and one for 2+4

Thanks

 

[JPJ2007]

 

[DGajre777]

Ok thanks for the heads up.
I was thinking about upgrading the turbo however I dont want to do too much
as to need to begin building internals.
I'll wait on the evo mani,
Im searching but how do I g about porting the o2 housing, the same goes for the t25.

Yeah I understand I'll throw a cel with the cat removed,
However, is the o2 behind the cat ONLY to make sure the cat is working correctly?
Or will this actually affect the performance of my gsx.

Im guessing its only to make sure the cat is working correctly as the first o2 is just behind the turbo to moniter the readings.

Im asking becuase my Motor I swapped in from Japan on my integra has two o2 sensors
One for cyl 1+3 and one for 2+4

Thanks

'Need to begin building internals'? 2G DSMs have gone up to about 400whp before needing to be built. If you want to stick to a T25 system, upgrade to a Big T28 from www.forcedperformance.net with their 17psi actuator, the GT manifold I mentioned which is sold at www.dsmparts.com and the o2 housing I mentioned from www.punishment-racing.com

The only o2 sensor you need to make your car work properly is the front o2 sensor. You don't need rear o2 sensor, the only purpose of the sensor is to make sure the cat works. Check the tech guide on how to make a rear o2 sensor simulator for about $15 from radioshack parts, I made one and it has been on my car for about a year now.

Check the upgrade path for more info on parts - and do a few searches, all your questions will be answered. If they don't, post again. Good luck with your setup.

 

[JPJ2007]

Thanks alot man.

I'll def read up and search my ass off.

I remember bein on Honda-Tech and thats the Hell of flaming
Noobs would always ask questions that could be searched for and
I and others would get pissed off.

But the tables are turned now and Im clueless.

But I'll search and thanks for helping me out already guys.

Def happy to be with dsm now. Just cant wait to be spankin some
ricers and v8 heads.

Well thanks again.

Oh btw. I talked to my local exhaust shop.
Im having a 3" off the o2 housing-3" flex pipe-3" piping to a Buddy Club Pro-Spec 3" turbo Racing Muffler Im buying.

So I cant wait to hear it growl.


Thanks again for being so helpfull.

 

[DGajre777]

Glad to be of help.