Confusion regarding T25, T3 and T4 turbine flanges
10-13-2009, 02:58 PM
#41
This drawing has the T25 flange, middle-left of page: http://www.turbobygarrett.com/turbob...2_3_20_new.pdf
This drawing has the T3 and T4 flanges: http://www.turbobygarrett.com/turbob...T3071R_new.pdf
T2.5 flange is 40 x 49.3 mm
T3 flange is 44.5 x 57.2 mm
T4 flange is 50.3 x 74.7 mm
The corners are radiused. The cross-sectional areas are as follows:
T2.5 flange is 1735 sq. mm
T3 flange is 2412 sq. mm
T4 flange is 3625 sq. mm
For reference, the turbine inlet area on a GT3582 0.76 A/R turbine is 1117 sq. mm. So, the T25 flange is about 55% larger than this particular turbine inlet, and the T3 flange is 116% larger. However, the flange is literally only couple of inches from the turbine inlet.
My point in all of this is that even if you enlarge the flange, you are only increasing the cross-sectional area over a couple of inches. The cross-sectional area still is going to be dropped down to that of the turbine inlet area. Being 116% larger rather than 55% larger than the turbine inlet a mere couple of inches from the turbine inlet will not make a significant difference. Moreover, with the larger flange, there is a sharper transition from the flange to the turbine inlet, which may be a little more disruptive to the exhaust flow (although even that may not be noticable). Considering the restrictions already present in a log style manifold, the change from a T25 flange to a T3 flange on a log style manifold will be insignificant for the size of turbos that we run. If someone is going to run a turbo with a 2000 sq. mm turbine inlet, OK, then there will be a difference. Nonetheless, that log style manifold would have to be significantly larger than the ones that are presently used on our cars. But nobody would run such a turbo and log style manifold because they will not fit in our engine bays.
Since nobody still makes a log style manifold with a T3 flange, it's probably a moot point. The reason I started this thread is because there still seemed to be some misunderstanding in the forum about the flanges, their dimensional relationships to the turbine inlets, and the consequences of these relationships.
Last edited by ttg35fort; 10-13-2009 at 03:23 PM.
10-13-2009, 05:49 PM
#42
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ah, from what i know about physics i completely understand what you are saying about the flange being oversized for the inlet having no increase in performance.
I would think that a flange closest to the size of the inlet would provide the smoothest flow. as long as it's not smaller than the turbo inlet there shouldn't be a restriction on it. you're exactly right at that.
I just didn't know the sizes and dimensions of the flanges.
I would think that a flange closest to the size of the inlet would provide the smoothest flow. as long as it's not smaller than the turbo inlet there shouldn't be a restriction on it. you're exactly right at that.
I just didn't know the sizes and dimensions of the flanges.
10-13-2009, 07:17 PM
#46
well if you can show me an oil sump that is not mounted under the tranny (low!), you might have a point. its not the pump, its the sump that can cause problems. But seeing the Thom is more or less the only one on here with a SP kit and he's basically at stock height, its hard to say.
I mean I want the SP kit to be a street and installer friendly kit, but every experienced tuner I speak to about that kit isnt too keen on it.
I mean I want the SP kit to be a street and installer friendly kit, but every experienced tuner I speak to about that kit isnt too keen on it.
Why do you think a scavenge pump would not let you lower the car? You can route it just find and not be in danger of hitting it.
The reason the single market on the Z is not real strong is because ITS A V MOTOR. Its easier to do twins to obtain higher horspower. There isnt a lot of engine bay room and the pipe routing can get to be a PITA.
The reason the single market on the Z is not real strong is because ITS A V MOTOR. Its easier to do twins to obtain higher horspower. There isnt a lot of engine bay room and the pipe routing can get to be a PITA.
10-13-2009, 07:30 PM
#47
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Sure, just to a lesser extent ( or rather different extent since the engine will be helping to push the gases along and pressure will rise ). The scroll of a turbo is designed specifically for this and also so that the gasses would distribute themselves better throughout the scroll and into the turbine. It's a lot of complex crap which I'm not an expert on fwiw...lol.
Last edited by GT-ER; 10-13-2009 at 07:31 PM.
10-13-2009, 10:49 PM
#48
That is correct if you assume that there is an increased amount of exhaust flow, but there won't be for a given rpm/throttle condition. So, the velocity of the exhaust flow through the turbine will be roughly the same for a given A/R. Of course, as you reduce the A/R, you increase the velocity of the exhaust flow, which helps to get the turbines to spool more quickly. The downside the a small A/R is there is more back pressure, and the angle at which the exhaust gases hit the turbine blades is less optimized for high flow volume.
Last edited by ttg35fort; 10-14-2009 at 12:32 PM.
10-14-2009, 06:08 AM
#49
Incorrect. Sam at GTM recommends his turbo kits for big power, and they only come with T25 flanges. There are two builds underway right now using the GTM turbo kits, and both are shooting for over 1000 whp.
Based on its design, a log style manifold is going to be restrictive. Merely changing out the flange to a T3 flange is not going to miraculously change the log manifold itself. imo, with a log style manifold, there won't be any significant difference at all between the T25 and T3 flange.
On a header style manifold, OK, then the T3 flange makes sense.
Also, show me a VQ35 log style manifold that is made with a T3 flange. One may exist, but I have never seen one. If one does exist, it would be interesting to see how well it fits, as well as compare its performance to the GTM exhaust manifold.
Based on its design, a log style manifold is going to be restrictive. Merely changing out the flange to a T3 flange is not going to miraculously change the log manifold itself. imo, with a log style manifold, there won't be any significant difference at all between the T25 and T3 flange.
On a header style manifold, OK, then the T3 flange makes sense.
Also, show me a VQ35 log style manifold that is made with a T3 flange. One may exist, but I have never seen one. If one does exist, it would be interesting to see how well it fits, as well as compare its performance to the GTM exhaust manifold.
LMFAO! Sam was rating some GTM products capable of 1000whp before you even joined this forum and as we both know on today's date 10-14-09, GTM has yet to produce a single 1000whp car on any platform, let alone a VQ. So Sam is recommending something for a power level that he has no quantitative personal experience with.
10-14-2009, 06:56 AM
#50
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well if you can show me an oil sump that is not mounted under the tranny (low!), you might have a point. its not the pump, its the sump that can cause problems. But seeing the Thom is more or less the only one on here with a SP kit and he's basically at stock height, its hard to say.
I mean I want the SP kit to be a street and installer friendly kit, but every experienced tuner I speak to about that kit isnt too keen on it.
I mean I want the SP kit to be a street and installer friendly kit, but every experienced tuner I speak to about that kit isnt too keen on it.
Last edited by thawk408; 10-14-2009 at 06:58 AM.
10-14-2009, 07:54 AM
#52
LMFAO! Sam was rating some GTM products capable of 1000whp before you even joined this forum and as we both know on today's date 10-14-09, GTM has yet to produce a single 1000whp car on any platform, let alone a VQ. So Sam is recommending something for a power level that he has no quantitative personal experience with.What is your opinion on Mike's build. GTM TT kit, JWT cams, do you think he will make his stated goal?
Do you think GTM's AutoBahn build will make 1000 whp?
How much power are you laying down?
Last edited by ttg35fort; 10-14-2009 at 09:15 AM.
10-14-2009, 11:28 AM
#54
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Str8,
That pic is of the shop car, so its a touch different than the kits. That was before they built their own reservoir.
Here is a pic of my car. Yes the reservoir is below the trans, but it still sits above the sub-frame crossmember. Granted the sub-frame "should" be the highest point going over a speed bump because its in line with the wheels, but you are going to be rubbing the body of the car before the reservoir. I'll try to remember to get some pics this week of mine with the car on the ground so you can see.
and yes the pump is tucked up higher. The res is more of a wedge shape, its not round like the one of the shop car (its powdercoated black on my car)
That pic is of the shop car, so its a touch different than the kits. That was before they built their own reservoir.
Here is a pic of my car. Yes the reservoir is below the trans, but it still sits above the sub-frame crossmember. Granted the sub-frame "should" be the highest point going over a speed bump because its in line with the wheels, but you are going to be rubbing the body of the car before the reservoir. I'll try to remember to get some pics this week of mine with the car on the ground so you can see.
and yes the pump is tucked up higher. The res is more of a wedge shape, its not round like the one of the shop car (its powdercoated black on my car)
10-14-2009, 12:05 PM
#55
Depends what your definition of big power is. I don't see a T25 flange/housing being too restrictive up to about 700-800whp...after that I would agree that T3 is the way to go up to maybe 1200-1400whp or so. Heck, I got almost 400whp ( 378whp to be exact ) out of a GT2871R with a T25 housing ( small .64 A/R to boot ) on an otherwise stock 1.8L 4 cyl. Getting twice that out of TWO GT3071R's with .86 T25 housings should be no problem. Then again....I'd shoot at those numbers with T3 housings simply because their is no doubt that they can flow more and there are more options as far as housings go ( gotta love those smooth GT housing ).
Oh no...we just got on topic....nooooooooooooooooo....
Oh no...we just got on topic....nooooooooooooooooo....
Other than Mike (XKR), GTM's Autobahn project, and a couple of shop cars, how many people are actually trying to break over 1000 whp on their builds? There has been so much debate lately on whether X components are good enough for over 1000 whp, it seems like there would be a lot more people trying to get there.
If anyone is shooting for 1000 whp on their build, please post here to give us the specifics on the build.
Thawk408, previously you stated that you did not consider 700 - 800 hp big hp. How much hp are you laying down? What is your build?
Last edited by ttg35fort; 10-14-2009 at 12:33 PM.
10-14-2009, 12:23 PM
#56
ah, from what i know about physics i completely understand what you are saying about the flange being oversized for the inlet having no increase in performance.
I would think that a flange closest to the size of the inlet would provide the smoothest flow. as long as it's not smaller than the turbo inlet there shouldn't be a restriction on it. you're exactly right at that.
I just didn't know the sizes and dimensions of the flanges.
I would think that a flange closest to the size of the inlet would provide the smoothest flow. as long as it's not smaller than the turbo inlet there shouldn't be a restriction on it. you're exactly right at that.
I just didn't know the sizes and dimensions of the flanges.
10-14-2009, 12:46 PM
#58
Registered User
Well my turbos, injectors, inner-cooler, and probably intake mani all run out at about 900rwhp (kinda planned it that way 
)
I am still not sold on the stock sleeves holding 1000rwhp, but I am anxious to see it happen.
Tom
)I am still not sold on the stock sleeves holding 1000rwhp, but I am anxious to see it happen.
Tom
In my setup, I'm using two GT3071R's with 0.64 A/R on a 4.0L motor. My goal is 675 whp on pump gas, and 750 whp with methonal injection. I have the GTM kit with the T25 flanges, and I do not anticipate I will have any problem getting there.
Other than Mike (XKR), GTM's Autobahn project, and a couple of shop cars, how many people are actually trying to break over 1000 whp on their builds? There has been so much debate lately on whether X components are good enough for over 1000 whp, it seems like there would be a lot more people trying to get there.
If anyone is shooting for 1000 whp on their build, please post here to give us the specifics on the build.
Thawk408, previously you stated that you did not consider 700 - 800 hp big hp. How much hp are you laying down? What is your build?
Other than Mike (XKR), GTM's Autobahn project, and a couple of shop cars, how many people are actually trying to break over 1000 whp on their builds? There has been so much debate lately on whether X components are good enough for over 1000 whp, it seems like there would be a lot more people trying to get there.
If anyone is shooting for 1000 whp on their build, please post here to give us the specifics on the build.
Thawk408, previously you stated that you did not consider 700 - 800 hp big hp. How much hp are you laying down? What is your build?
10-14-2009, 01:12 PM
#59
As far as the sleeves go, I have GTM welding in supports for the upper portion of the cylinders to add some stability, kind of like the HR block design. Since mine is the first VQ block he is doing that to, he is taking extra time to make sure everything is good.
Last edited by ttg35fort; 10-14-2009 at 01:37 PM.
10-14-2009, 02:41 PM
#60
thats why its so hard to compare kits. YOu say you had alot of headroom on your 18g's, yet there was just a 18g @18psi on C16 dyno posted, it only made 536 hp with the exact parts that I have (c2 cams, cosworth, big fuel....)
Unless the tuner left a 100 horses or so on the table, the parts are much greater than the whole.
Unless the tuner left a 100 horses or so on the table, the parts are much greater than the whole.