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MODIFICATIONS => Performance => Topic started by: killinprixs on April 06, 2007, 02:23:42 PM

Title: Cylinder Heads HIGHER FLOW
Post by: killinprixs on April 06, 2007, 02:23:42 PM
I feel like I have more turbo than i do power,  maybe because i slapped on 2.8 heads (26cc) because they were the only nonwarped heads i had.   I need the 28cc heads,  if i use the 511 (28cc ) heads and had them ported, how much power would that free up with about 10 psi?  I know the heads im using are a restriction.    thanks guys,
Title: Re: Cylinder Heads HIGHER FLOW
Post by: sleeperred90tgp on April 06, 2007, 08:10:08 PM
Stock T25 turbo?
Title: Re: Cylinder Heads HIGHER FLOW
Post by: kuntzie on April 06, 2007, 08:19:18 PM
ya befinitly not getting more turbo then power... also for what its worth... some 2.8 heads are 100% identical to the 3.1s ones.... and even more so they would only affect the compression ratio.
Title: Re: Cylinder Heads HIGHER FLOW
Post by: killinprixs on April 06, 2007, 09:52:34 PM
Stock T25.  I think it runs 8.8 compression right now, but wouldnt the smaller cc restrict some of air that is being compressed therefore making less power?  I have a set of 1.6 rockers to put on too.   I know this car can be faster ...  quick questio,  i thought the computer was supposed to cut fuel at 8 psi?  I rigged up a vaccum boost controller and my stock guage is running around 10.  I can set the controller to run up to 15 but i dont want to do that.     Is this because i unpluged the stock boost controller?  The title of the car was issued Dec 31,1990 so i was wondering if it had a different chip or something.   
Title: Re: Cylinder Heads HIGHER FLOW
Post by: TGP Nick on April 06, 2007, 10:13:04 PM
I have a BONE stock TGP, and every once in a while, mine will hit ~10 PSI of boost with no fuel cut or anything.  I've really only hit fuel cut with it once....
Title: Re: Cylinder Heads HIGHER FLOW
Post by: kuntzie on April 06, 2007, 10:13:25 PM
the factory bosst gague is a 100% inaccurate piece of shit.. and the top end makes no differece as i said earlier.. the headds are a minor difference (if they actually are diffferent) and the intakes are identical (minus the writing)
Title: Re: Cylinder Heads HIGHER FLOW
Post by: TGed on April 07, 2007, 09:44:57 AM
There is one difference in teh UIM and lower intake manifold. The hose for the PCV valve connects to the UIM on the 3.1 where as the 2.8 connects to the LIM.  You could tap and thread the lim or uim for whatever your needs are for the hose, but that is a difference.

;)
Title: Re: Cylinder Heads HIGHER FLOW
Post by: kuntzie on April 07, 2007, 09:58:33 AM
Quote from: TGed on April 07, 2007, 09:44:57 AM
There is one difference in teh UIM and lower intake manifold. The hose for the PCV valve connects to the UIM on the 3.1 where as the 2.8 connects to the LIM.  You could tap and thread the lim or uim for whatever your needs are for the hose, but that is a difference.

;)

well i have 2 different plemums for the 3.1 turbos.. one has the 2.8 style pcv and the other is the 90 + ( so my 89 tgp has a 2.8 style pcv valve connector)
Title: Re: Cylinder Heads HIGHER FLOW
Post by: TurboGTU on April 10, 2007, 11:38:36 PM
Only way you'll gain anthing is by porting the exhaust ports. In the chamber..the exhaust valve is already unshrouded. Just go all out on the exhaust ports. The intake flows plenty, if anything..the intake manifold is a restriction. The exhaust ports and the intake manifold are designed with low end torque in mind. On the heads the exhaust flows 110 cfm and the intake flows about 185cfm.
But even then...the stock turbo isn't enough for this motor. Step up to a larger turbo before even pulling the heads.
Title: Re: Cylinder Heads HIGHER FLOW
Post by: Shifter23 on April 29, 2008, 07:13:18 PM
What would be a better turbo?  I was offered a T28 ball bearing for a silva S15 that is internally gated.  Would that be a good start i have also been told about the T25/28 hybrid.  Hopefuly my question benifits the poster and me.
Title: Re: Cylinder Heads HIGHER FLOW
Post by: grinders_18 on April 29, 2008, 07:18:47 PM
Here's my honest input on the T-28 Hybrid, since I own one.

Pros:
- spools MUCH faster
- increased speed is there and FELT
- direct bolt on

Cons:
- still a small turbo, but without any large top end modifications, you don't NEED bigger.
- price...now you will be able to get one cheaper and doing the work yourself is a plus...I paid too much.

Overall, if my turbo ever went bad, I'd park the car and do some engine work, then upgrade the turbo to a t-3 series, as well as upgrade the exhaust. With a stock setup, T-28 is plenty big. With my setup, a very decent amount of work, it's still very good.
Title: Re: Cylinder Heads HIGHER FLOW
Post by: killinprixs on April 29, 2008, 11:18:56 PM
jonny B bad
Title: Re: Cylinder Heads HIGHER FLOW
Post by: mfewtrail on April 30, 2008, 01:18:15 AM
Quote from: Shifter23 on April 29, 2008, 07:13:18 PM
What would be a better turbo?  I was offered a T28 ball bearing for a silva S15 that is internally gated.  Would that be a good start i have also been told about the T25/28 hybrid.  Hopefuly my question benifits the poster and me.

Those Nissan T28's are typically going to take a good bit of work to bolt on to a TGP. I would go another route...
Title: Re: Cylinder Heads HIGHER FLOW
Post by: grinders_18 on April 30, 2008, 05:19:29 AM
Quote from: mfewtrail on April 30, 2008, 01:18:15 AM
Quote from: Shifter23 on April 29, 2008, 07:13:18 PM
What would be a better turbo?  I was offered a T28 ball bearing for a silva S15 that is internally gated.  Would that be a good start i have also been told about the T25/28 hybrid.  Hopefuly my question benifits the poster and me.

Those Nissan T28's are typically going to take a good bit of work to bolt on to a TGP. I would go another route...
That's why you buy the T-28 kit and build it in your T-25 shell...thus creating the T-28 Hybrid.

Hey can someone explain what a manual boost controller does? How hard is it to upgrade the wastegate?
Title: Re: Cylinder Heads HIGHER FLOW
Post by: killinprixs on April 30, 2008, 04:40:06 PM
i like chicken
Title: Re: Cylinder Heads HIGHER FLOW
Post by: grinders_18 on April 30, 2008, 04:46:23 PM
Ok, so how long of a spring, and what thickerness am I looking for? That's it though? It's just loops exactly where he has it? Seriously lol?
Title: Re: Cylinder Heads HIGHER FLOW
Post by: meltboy11 on April 30, 2008, 05:17:50 PM
what would one of these boost controllers cost and where is a good place to get one?
Title: Re: Cylinder Heads HIGHER FLOW
Post by: grinders_18 on April 30, 2008, 05:22:32 PM
X2. I see some on eBay from time to time, but they all say professional installation recommended. Is that really needed?
Title: Re: Cylinder Heads HIGHER FLOW
Post by: jimmy on April 30, 2008, 06:13:35 PM
         I don't think so Kyle, it does surprize me that you didn't know that. I know at one time I had 2 of those just to hold it close, cause mine has a terrible leak on it. Thats why I can't wait to slap a bigger Turbo just to get rid of that sorry ass T-25  :icon_rolleyes:
Title: Re: Cylinder Heads HIGHER FLOW
Post by: grinders_18 on April 30, 2008, 06:18:45 PM
Jimmy, the fact that a regular spring could do that surprises me. The fact that a manual boost controller doesn't need a pro install doesn't surprise me...just wanted to cover all bases before I try and get one :icon_wink: Better safe than sorry, right?
Title: Re: Cylinder Heads HIGHER FLOW
Post by: TGP Nick on April 30, 2008, 07:31:11 PM
So wait.. if you are running a chip set to run with more boost than stock, and the stock wastegate opens at 4 PSI, it just bleeds off the extra boost that is supposed to be produced??... I am finding this hard to believe.  Are there any harmful effects of running a spring to hold the wastegate closed?
Title: Re: Cylinder Heads HIGHER FLOW
Post by: meltboy11 on April 30, 2008, 08:34:48 PM
I think I remember seeing on a thread recently that having it constant was a bad thing... I  also didn't know that the stock setup was only 4 psi... that sux... I want more... lol
Title: Re: Cylinder Heads HIGHER FLOW
Post by: Shifter23 on April 30, 2008, 09:14:54 PM
Where is the best place to get a T28 upgrade kit i have a spare turbo with my second car in the trunk i want to rip and tear now!  Do i have to chip it for the T28?
Title: Re: Cylinder Heads HIGHER FLOW
Post by: killinprixs on April 30, 2008, 11:51:08 PM
i like apples too
Title: Re: Cylinder Heads HIGHER FLOW
Post by: killinprixs on May 01, 2008, 12:03:43 AM
didnt seem like anyone likes videos or burnouts around here so i took it down... haha
Title: Re: Cylinder Heads HIGHER FLOW
Post by: grinders_18 on May 02, 2008, 05:11:27 AM
Shifter, you will not need to get a chip for a T-28.
Title: Re: Cylinder Heads HIGHER FLOW
Post by: Bullet on May 02, 2008, 09:50:15 AM
go one size up if you're going to port your heads. I'd do a T3/T4 50 trim, but not let the PSI go over 8.5. yeah it will take a split second longer to spool but its cheap porwer condidering you can get one for $150 shipped to your door.
one of my buddies bought one about a year ago and has put over 20k on it with no issues yet.

PM me for details
Title: Re: Cylinder Heads HIGHER FLOW
Post by: grinders_18 on May 02, 2008, 01:31:50 PM
grandprixagain, why did you take down the info about the spring? I read it this morning, but I was damn near alseep when I read it...
Title: Re: Cylinder Heads HIGHER FLOW
Post by: killinprixs on May 02, 2008, 01:35:45 PM
figured it was off topic here
http://www.tgpforums.com/index.php?topic=3591.0 (http://www.tgpforums.com/index.php?topic=3591.0)
Title: Re: Cylinder Heads HIGHER FLOW
Post by: grinders_18 on May 02, 2008, 01:44:23 PM
God no! I appreciate your input  ;)
Title: Re: Cylinder Heads HIGHER FLOW
Post by: a1990cavalierz24 on June 11, 2008, 01:23:15 PM
Quote from: grinders_18 on April 30, 2008, 05:19:29 AM
Quote from: mfewtrail on April 30, 2008, 01:18:15 AM
Quote from: Shifter23 on April 29, 2008, 07:13:18 PM
What would be a better turbo?  I was offered a T28 ball bearing for a silva S15 that is internally gated.  Would that be a good start i have also been told about the T25/28 hybrid.  Hopefuly my question benifits the poster and me.

Those Nissan T28's are typically going to take a good bit of work to bolt on to a TGP. I would go another route...
That's why you buy the T-28 kit and build it in your T-25 shell...thus creating the T-28 Hybrid.

Hey can someone explain what a manual boost controller does? How hard is it to upgrade the wastegate?

So where do you get the T28 kit at? I am interested in doing this swap as well.
Title: Re: Cylinder Heads HIGHER FLOW
Post by: grinders_18 on June 11, 2008, 04:04:04 PM
www.gpopshop.com

Gerry is the one to talk to, tell him Kyle Krenz sent you. But be prepared to pay a little extra.
Title: Re: Cylinder Heads HIGHER FLOW
Post by: a1990cavalierz24 on June 14, 2008, 10:41:28 AM
Quote from: grinders_18 on June 11, 2008, 04:04:04 PM
www.gpopshop.com

Gerry is the one to talk to, tell him Kyle Krenz sent you. But be prepared to pay a little extra.

So do you have any numbers as to what kind of hp gain you got by doing the T28 hybrid turbo? I am just looking for some ballpark hp numbers is all.