Which turbo setup to take? (turbo+wastegate+Ex.manifold)

[2plus4plus0eq6]

I am confused on which way to go. Here are some options I am considering:

Internal wastegate or external wastegate
First of all, I am looking into getting a Garrett T28RS 'Disco Potato' because I want the quick spool. My HP goal is about 300-350 rwhp and looking for more low-to-mid end. I am also considering other Garret GT turbos out there without an internal wastegate. My budget for turbo+wastegate is about $1300 USD

Can someone please explain to me if wastegates make big differences and which path I should take (turbo with internal/external wastegate)? If it has been talked about already, then just point me in the right direction. I believe the external ones are adjustable and therefore more efficient?

Bottom Mount or Top Mount Exhaust Manfiold
Anyone know where I can find some good specs on the OBX SR20DET Top Mount manifold? Also, where I can buy one instead of Ebay?
Im asking because I believe the flange on it will fit the T28RS, but I want to make sure.

If I were to go with a Top Mount, would I need to get a different kind of downpipe which is specifically designed for a top mount exhaust manifold? If so, What are my choices?

[steve shadows]

honestly if you only looking for that power.

Go with a gt28 varient, and spend some time on some decent cams, valve springs if needed and a standalone that you are comfortable with.

[2plus4plus0eq6]

Sorry don't mind me, but what do you mean by GT28 varient?

I will eventually get some nice cams and all of that stuff, but for now I don't want to touch any internals since I am still very new to mechanics.

Because I blew my stock T28, I want to replace that turbo and I figure that I might aswell replace the manifold, turbo elbow, and downpipe while I am at it.

[steve shadows]

what i mean by that is

T28 turbine based bolt on turbo. with internal WG.

I hate IWG but if you can upgrade to a HKS actuator and use a good boost controller it will get you to a stable 340whp range with a set of 260 duration cams with at least 11 mm of lift.

GT2871R 380whp
GT2560R 320whp

those would be my choices as options

the second one is commonly called or mis-called the disco potatoe

[MomentumGT]

I am confused on which way to go. Here are some options I am considering:

Internal wastegate or external wastegate
First of all, I am looking into getting a Garrett T28RS 'Disco Potato' because I want the quick spool. My HP goal is about 300-350 rwhp and looking for more low-to-mid end. I am also considering other Garret GT turbos out there without an internal wastegate. My budget for turbo+wastegate is about $1300 USD

Can someone please explain to me if wastegates make big differences and which path I should take (turbo with internal/external wastegate)? If it has been talked about already, then just point me in the right direction. I believe the external ones are adjustable and therefore more efficient?

Bottom Mount or Top Mount Exhaust Manfiold
Anyone know where I can find some good specs on the OBX SR20DET Top Mount manifold? Also, where I can buy one instead of Ebay?
Im asking because I believe the flange on it will fit the T28RS, but I want to make sure.

If I were to go with a Top Mount, would I need to get a different kind of downpipe which is specifically designed for a top mount exhaust manifold? If so, What are my choices?

If you're going with the gt28rs no need to buy the obx top mount mani. Your stock mani or a megan (don't hate on me guys) come with the T2 flange and can bolt the gt28rs directly. Also no need to make a custom dp or turbo elblow. I thought all top mount mani's came T3 flanged, but if if comes with a T2 flange that would be really gehy.

If going top mount I'd go with a 3071 or something like that, but that won't fit in your budget.

-Jon

[DJ_Sunrise]

Wastegates = Boost controllers
Once a certain PSI is reached, a valve opens, venting excess boost.

External wastegates are more precise and reliable = less chance of boost creep, over boost, etc. Internal wastegate can be adjustable as well.. But.. theres not much of a reason for it to matter since 99% of the time an additional boost controller will be mounted = Manual boost controller, or electronic boost controller. The adjustability of the WG comes in as a boost controller. Most hardcore race cars I see use external wastegate as the only boost controller, because of their rock solid reliability. Plus.. the less equipment you have, the less shit you have to break, like an electronic boost controller...Machines have a solid tendency to work. Electronics have a MUCH shorter life span.. Do you really want to put the life of your motor in the hands of electrons and copper wire? I don't.

I don't trust OBX.. Reminds me of Megan. Blah. At any rate, yes, a topmount will require a different down pipe. If you stick to a T25 Flange, than any T25/T28 exhaust manifold will work..

In your shoes I would PM Steve Shadows, send him a T28, tell him you want 350whp and wait for him to send you the turbo back. In the week down time you have, install 740cc Nismo/Tomei/Apexi Injectors and a fuel pressure regulator. I would also put on a Tomei Expreme exhaust manifold ($600) they are absolutely amazing, and dozens of members will vouch for it. It seems to aid in tq., so you can walk away with larger AR turbos.. You WILL need a standalone, or a reflash. I don't know shit about reflashes, I personally just went to an Apex'i Power FC. After that's all said and done..Take your car to get tuned.

-Bart

[2plus4plus0eq6]

OK thanks for the help. I am slowly starting to understand more now. FYI, I aleady have a TurboXS single stage boost controller. I don't plan on boosting anything crazy like 25, so I assumed this would be good enough for me.

Everything I want to do to my car will be external mods for now. I will definitely get some nice cams like Steve was suggesting.

As for the OBX top mount, I heard they are crap too. A buddy of mine already cracked one of their manifolds on his eclipse. I was just curious because I thought I saw somewhere that it said it was compatiable with the T28. Another reason I want Top mount is because I can see the pretty turbo infront of me, but I guess what you are saying is that if its a T2 turbo, it will be a joke ;)

MomentumGT, I am considering the Megan Racing manifold or the even a tomei one if I can squeeze out some extra cash.

DJ_Sunrise, I hate sending stuff away since I am in Canada. Takes so long and all. Just a pain. I will get a new turbo no matter what and probably just get a rebuild kit and I will try and rebuild my T28 for fun lol and learn something while I'm at it. As for the tuning and all, I will probably go with the Apexi Power FC like you did and give it a good tuning.

Do you guys know what rpm range the GT28RS and the GT2871R both start to spool at?

[steve shadows]

OK thanks for the help. I am slowly starting to understand more now. FYI, I aleady have a TurboXS single stage boost controller. I don't plan on boosting anything crazy like 25, so I assumed this would be good enough for me.

Everything I want to do to my car will be external mods for now. I will definitely get some nice cams like Steve was suggesting.

As for the OBX top mount, I heard they are crap too. A buddy of mine already cracked one of their manifolds on his eclipse. I was just curious because I thought I saw somewhere that it said it was compatiable with the T28. Another reason I want Top mount is because I can see the pretty turbo infront of me, but I guess what you are saying is that if its a T2 turbo, it will be a joke ;)

MomentumGT, I am considering the Megan Racing manifold or the even a tomei one if I can squeeze out some extra cash.

DJ_Sunrise, I hate sending stuff away since I am in Canada. Takes so long and all. Just a pain. I will get a new turbo no matter what and probably just get a rebuild kit and I will try and rebuild my T28 for fun lol and learn something while I'm at it. As for the tuning and all, I will probably go with the Apexi Power FC like you did and give it a good tuning.

Do you guys know what rpm range the GT28RS and the GT2871R both start to spool at?

spool depends on a lot of things

back pressure
cam size
tuning
timing
and more.

in general the gt28rs will get full boost by 3200 rpms

2871R is close behind at around 3800-4200 depending on boost and variables.

[2plus4plus0eq6]

hmm interesting..

GT28RS Full boost at 3200 so it starts to spool at like 2600-2800?
Thats pretty much what I am looking for.

Steve, if I were to get the 2871R and bigger cams, would I theoretically reach full boost sooner than 3800-4200 or even later?

Thanks

[steve shadows]

well funny enough in my experience back pressure can effect your spool time just as much as cam timing but of course more bp equals more torque drop off at high rpms.

anyways thats a tangent

in your case larger cams will affect the usable power curve not so much spool up. 264-260 deg cam intake and exaust with no more than 11.5 mm of lift is what I would suggest.

Then go with the .64 turbine housing 2871R.

It is the sht.

With that you should be able to get full spool and torque to start coming on hard around 4200 rpms at the latest with a greddy IM.

With a stock IM you will have power at more of the 3800 rpm range or even sooner depending on your timing maps on your tune.

go source up some dynos.

[2plus4plus0eq6]

I will look up some dynos on the GT28RS and the 2871R for comparison. I am starting to lean more towards the 2871R now since it has more HP capabilities, but I've also heard that it has some turbo lag.

Chances are I will get the Megan racing bottom mount manifold and a circuit sports turbo elbow and downpipe with that. Anyone recommend the ichiba Exhaust Manifold v2? I know it says its a 4-2-1 design whatever that means.

Later on, I will get new cams, valve springs, metal head gasket, and the Greddy Intake manifold like you suggested. Hopefully not that much later, because I only want to tune my car once and for all.

Quick question - Does it matter if the Intake and exhaust cams are different durations? Or should I be sticking with the same size as a rule of thumb?

[steve shadows]

I will look up some dynos on the GT28RS and the 2871R for comparison. I am starting to lean more towards the 2871R now since it has more HP capabilities, but I've also heard that it has some turbo lag.

Chances are I will get the Megan racing bottom mount manifold and a circuit sports turbo elbow and downpipe with that. Anyone recommend the ichiba Exhaust Manifold v2? I know it says its a 4-2-1 design whatever that means.

Later on, I will get new cams, valve springs, metal head gasket, and the Greddy Intake manifold like you suggested. Hopefully not that much later, because I only want to tune my car once and for all.

Quick question - Does it matter if the Intake and exhaust cams are different durations? Or should I be sticking with the same size as a rule of thumb?

Im not a big fan of staggering durations unless you are trying to do something out of the ordinary.

256 intake with 264 exaust hks step 1 has been popular with the response crowd because of its quick build in overlap and it complements the smalelr turbines natural power band on the sr20.

I would personally say if your going to retain the stock IM (which i reccomend for response) use the 264 step1 on both intake and exaust (or tomei 260 pro-cams). As always make sure your Valve springs are up to the task. I would reccomend upgrading them.

[2plus4plus0eq6]

Ya I have been considering the Tomei and the HKS ones. Thanks a lot for the help. I will do some more research when I am closer to getting some internals.