Twin GT28r Turbo Kit Pics
Rotary Freak
Joined: Jan 2002
Posts: 1,643
Likes: 0
From: l.a.
Originally Posted by z8cw
Looking for some confirmation here but that is what I think.'
Stock port, flows max of 40 lbs/min at 15 PSI, 46 at 20 PSI, 58 at 30
Street ports (big range but best I've seen) 47, 54, 68
Bridge port (big range again) 51, 57,71
PP 58, 66, 82
Looks to me that most twins are overkill for stock or not so great street ports. I would think the 28r is probably the best choice for most.
Stock port, flows max of 40 lbs/min at 15 PSI, 46 at 20 PSI, 58 at 30
Street ports (big range but best I've seen) 47, 54, 68
Bridge port (big range again) 51, 57,71
PP 58, 66, 82
Looks to me that most twins are overkill for stock or not so great street ports. I would think the 28r is probably the best choice for most.
Senior Member
Joined: Jan 2004
Posts: 341
Likes: 0
From: Colorado
The numbers are for the engine. These are possible flow numbers and are an average I backed out from dyno numbers and the information I had about the engines and the runs. It is a little crued but the only thing that is available. The numbers make sense if you try and match up compressor maps. You will see that for example the so popular GT35r matches up nicely with a stock or even better street port at the boost we typically running.
CW
CW
Originally Posted by Jason
We just got our first kit in today. Looks great and will be doing testing on it soon.
Jason
Jason
rain + FD = oops
Joined: Jan 2005
Posts: 72
Likes: 0
From: so Cal
Originally Posted by SnowmanSteiner
First off, thanks for immediately making snide comments. Next what I ment by in complete theory, was to take everything into theory, ie. no friction all gases and other elements act ideal. I did not mean that it was the complete end all of theories, misunderstanding but thanks for the insult.
A. I realize that these turbos are not half the size of any turbo, that's why I said "Let's say the turbos are exactly 1/2 the size of some specific single turbo." which means that we are simplifying things by taking an easy ratio. Again misunderstanding whatever.
B. I don't understand this, you'll have to elaborate further, I can't just assume it's right.
C. I don't think we are thinking the same things on this either. They way I am looking at it, is in a torque perspective. Ie. force x distance. Regardless you're final statement is correct, it does take more force to spin one larger wheel vs two.
D. The fact that the two turbos will spool individually faster is understood. But I have been told varying things on this subject, ie. some have said that the actually boost pressure that is made is the combination of both turbos, ie. if they are each producing 7lbs, then total they will produce 14lbs. But I've heard the opposite as well, that if they are both making 7lbs, then together they are still only making 7lbs unless you run an individual ic and runner all the way to the port.
additional turbo life, possibly, you also have to take into account that they are going to give off more heat than a single, by the same pricinple more surface area. More oil doesn't neccessarily mean that they will run cooler, oil can only absorb so much, and as I'm sure you know, there is a maximum point to where too much oil just isn't adding any benefits. Again it will take more oil to cool the system so the increase in amount of oil in the system should ballance this out, because you don't want to overflow what the stock system can take.
In my opinion if you want faster spool there are many devices on the market that can offer it at price that is much less than this. But as stated before some people want to do something different, which is why I think this kit has been developed.
- Steiner
A. I realize that these turbos are not half the size of any turbo, that's why I said "Let's say the turbos are exactly 1/2 the size of some specific single turbo." which means that we are simplifying things by taking an easy ratio. Again misunderstanding whatever.
B. I don't understand this, you'll have to elaborate further, I can't just assume it's right.
C. I don't think we are thinking the same things on this either. They way I am looking at it, is in a torque perspective. Ie. force x distance. Regardless you're final statement is correct, it does take more force to spin one larger wheel vs two.
D. The fact that the two turbos will spool individually faster is understood. But I have been told varying things on this subject, ie. some have said that the actually boost pressure that is made is the combination of both turbos, ie. if they are each producing 7lbs, then total they will produce 14lbs. But I've heard the opposite as well, that if they are both making 7lbs, then together they are still only making 7lbs unless you run an individual ic and runner all the way to the port.
additional turbo life, possibly, you also have to take into account that they are going to give off more heat than a single, by the same pricinple more surface area. More oil doesn't neccessarily mean that they will run cooler, oil can only absorb so much, and as I'm sure you know, there is a maximum point to where too much oil just isn't adding any benefits. Again it will take more oil to cool the system so the increase in amount of oil in the system should ballance this out, because you don't want to overflow what the stock system can take.
In my opinion if you want faster spool there are many devices on the market that can offer it at price that is much less than this. But as stated before some people want to do something different, which is why I think this kit has been developed.
- Steiner
just reading through this thread as I'm considering the dual twins also. Steiner, what Kevin is trying to say is that the rotational intertia of a disc or cylinder scales as the radius from the center SQUARED. I = mr^2. So if you have a disc that is half the diameter of another disc, then its rotational intertia will be one quarter of that of the bigger disk. thus 1/4 + 1/4 = 1/2 != 1 . Rotational inertia is another way of saying how much force it takes to get the object to spin, just like regular inertia is the amount of force it takes to get an object moving in a straight line. Same theory applies to flywheels and why it is such an important upgrade for road racers. I hope this clears up the nonlinearity that you were unclear about.
-hrach
WWFSMD
Joined: Jun 2001
Posts: 5,035
Likes: 4
From: SoCal
If you measured the pressure at the outlet of each compressor, and compared it with the pressure after the compressor outlet tubes are combined, you will find that the pressures are about the same. It won't be Pturbo1 + Pturbo2 = Pcombined.
-Max
-Max
Joined: May 2004
Posts: 2,988
Likes: 0
From: Home of the 305 Boyz(miami)
Ill bet my car that these will become soooo popular and more reliable than the the single. except for the heat.
bet it will make 500 easily on pump gas
bet it will make 500 easily on pump gas
Originally Posted by darkphantom
Ill bet my car that these will become soooo popular and more reliable than the the single. except for the heat.
bet it will make 500 easily on pump gas
bet it will make 500 easily on pump gas
You wanna put that in writing??? I'll take the bet about the popularity and about the easy 500 on pump gas.
Edan
Ga-nome liberator
Joined: Jul 2002
Posts: 1,990
Likes: 0
From: Hell
Originally Posted by fallenengel
just reading through this thread as I'm considering the dual twins also. Steiner, what Kevin is trying to say is that the rotational intertia of a disc or cylinder scales as the radius from the center SQUARED. I = mr^2. So if you have a disc that is half the diameter of another disc, then its rotational intertia will be one quarter of that of the bigger disk. thus 1/4 + 1/4 = 1/2 != 1 . Rotational inertia is another way of saying how much force it takes to get the object to spin, just like regular inertia is the amount of force it takes to get an object moving in a straight line. Same theory applies to flywheels and why it is such an important upgrade for road racers. I hope this clears up the nonlinearity that you were unclear about.
-hrach
-hrach
That's all I needed. Now his statements make more sense. Thanks. And thank Maxcooper for clearing up the issue with boost pressure.
- Steiner
Senior Member
Joined: Jan 2004
Posts: 341
Likes: 0
From: Colorado
All the turbos we typically run on our 7s flow enough air at 15 to 20 PSI to properly support our engines' need. If anything most turbos could flow more than the engines can digest. So, peak HP won't be any higher. The only difference with the twin set-up could be spool up time which I expext to be quicker than any single set-up. Still, lots will depend on the quality of the manifold.
CW
CW
I live in a Museum
Joined: Apr 2004
Posts: 928
Likes: 0
From: NY, 10992
Originally Posted by z8cw
All the turbos we typically run on our 7s flow enough air at 15 to 20 PSI to properly support our engines' need. If anything most turbos could flow more than the engines can digest. So, peak HP won't be any higher. The only difference with the twin set-up could be spool up time which I expext to be quicker than any single set-up. Still, lots will depend on the quality of the manifold.
CW
CW
Rotary Enthusiast
Joined: Jun 2004
Posts: 1,457
Likes: 0
From: Gallatin, TN
Originally Posted by iluvmy3rdgen
If the twins are ran in sequential then it's a possibility, but I highly doubt it's possibly for a twin setup in nonsequential will spool faster then a smaller single.
-Alex
Senior Member
Joined: Jan 2004
Posts: 341
Likes: 0
From: Colorado
The 28r are small turbos and 2 of them will flow about the same as one 35r. To compare spool up you need to compare turbos that will have the same HP potential at certain boost. Lets see what Jason can come up with. I am certainly curious. The only real draw back I see with two smaller singles is that they will not support higher boost. You find a lot more larger singles that can support high boost than smaller singles for a twin set-up. The twin set-up is certainly for the road racer not the drag or dyno queen. A large single won't work well at low boost on the street but you can still drive the car and kick butt at the drag strip on weekends. Two small singles will not produce higher boost ever but will kick butt on the road course and will be a great daily driver. So make sure you know what you want. (all theory here still waiting for Jason)
CW
CW
"Challenged" since 1993
Joined: Sep 2002
Posts: 540
Likes: 0
From: Columbus, Oh
Originally Posted by z8cw
The 28r are small turbos and 2 of them will flow about the same as one 35r. To compare spool up you need to compare turbos that will have the same HP potential at certain boost. Lets see what Jason can come up with. I am certainly curious. The only real draw back I see with two smaller singles is that they will not support higher boost. You find a lot more larger singles that can support high boost than smaller singles for a twin set-up. The twin set-up is certainly for the road racer not the drag or dyno queen. A large single won't work well at low boost on the street but you can still drive the car and kick butt at the drag strip on weekends. Two small singles will not produce higher boost ever but will kick butt on the road course and will be a great daily driver. So make sure you know what you want. (all theory here still waiting for Jason)
CW
CW
I dont see 500 rwhp from this set-up. What I expect to see is a remarkably quick spool combined with a very nice top end that will, from a roll, make the big single guys have to do some serious catch-up to get by me before 125 MPH or even higher.
My old set-up:
RX7Store Race-Ported motor*Rotary Aviation apex seals*Ported and polished exhaust manifold*Non-sequential ported stock turbos* Apex'i PFC w/Commander*Greddy FMIC *Greddy Profec B spec II*Ported UIM & TB*Greddy intake elbow*Efini Y-pipe*Unorthodox Racing main pulley and P/S pulley*Greddy underdrive pulleys*1680cc - 850cc injectors*Polished Billet fuel rail* SX Fuel pressure regulator*Denso Supra TT & Walbro fuel pumps*B&M New Volt ignition amp*GM 3-Bar MAP sensor*ACT street/strip clutch*Polished aluminum AST*PWR polished aluminum radiator*Oddessy micro-battery*silicone vacuum hoses* cheapass front strut bar*Airinx intake*Polished aluminum intake hardpipes*M2 SS downpipe*RX-7 Store SS midpipe*Racing Beat dual tip cat-back*S4 TII LSD*Dual A-pillar guage pod*Defi guages*Apexi autotimer*JDM ashtray arm rest*Mazdaspeed leather shift *****leather shift & e-brake boots*Scoot CF hood*Efini badging*99 spec front lip spoiler*BananaRE upgraded 93 spec turn lamps* 98 spec Type RZ spoiler*99 spec tail lamp conversion*Tokico Illumina 5 way adjustible*Racing Beat 2" drop springs*SSR Integral 18x9s wrapped in Toyo Proxes T1-S 255/35/18s
11.83 @ 116 on ET streets
385 rwhp @ 15psi
We will be comparing my previous dyno graphs, along with some other single
set-ups, as soon as we can get it on the dyno.
Originally Posted by t-von
To hell with peaky HP! I want I nice broad power band. I think the two BB twins will accomplish this.
Last edited by Rotarded; Feb 28, 2005 at 12:09 AM.
