renkenkyo

iTrader: (6)

Hi Guys,

My stock turbos are leaking pretty bad so I'm looking to upgrade to single since I will have to replace the stockers. I'm trying to find the right size using this calculator.

http://www.squirrelpf.com/turbocalc/

However, I'm not sure what numbers to use in some of the fields such as engine size and BSFC.

I'm aiming for purely road race applications, not interested in big power. I'm aiming for about ~340 - 360 BHP and want the turbos to be quick spooling. Do you guys have any suggestions as far as turbos?

ScorpionT

iTrader: (3)

Quite a few options. Whats your budget? Do you have a brand preference? You want 340-360 max, or will that be the average daily?

thewird

iTrader: (8)

A Precision billet 6262 with a T4 divided 0.86 housing is what your asking for. Well, its capable of more if you run higher boost.

But don't be scared to have a little more power for road racing, you get used to it quick and want more. So unless you want to autocross where you don't have any real straights I'd suggest a Precision billet 6265 with a T4 divided 0.86 housing. It'll still spool quick but give you some more juice. I mention the Precisions because they're affordable for what you get.

thewird

Turblown

iTrader: (12)

57 trim To4E spools even faster than mentioned above turbos, and will provide low exhaust manifold back pressure.

We've also got single turbo kits in stock, ready to ship

renkenkyo

iTrader: (6)

No real preference as far as brands are concerned, but the Garrett or BW or KKK are some of my top picks. My budgets about 12K for everything: intercooler, turbo, radiator, piping/manifold, intake, mid pipe, cat-back, ECU, tuning

Any ideas on the number to put in for equivalent liters?

ScorpionT

iTrader: (3)

You could put 2.6 in the calculator. However, its probably easier to get advice from the forum.

I would personally use a divided housing, you will get the best spool and efficiency. When it comes down to turbos, a Precision 5857 or 6262 with a divided housing would work well. The 6262 is a bit more than you would need (even on pump fuel), but Im just not sure how the 5857 would work so I cant really say which would work better.

The BW S256 (aka 75/70) would be a good choice, it would max around 450whp so 360whp would not be too difficult.

Indian

iTrader: (1)

you know.. Im far from knowledgeable compared to the guys that have posted already, but maybe you want to check out the apexi rx6. I know its an older turbo but, it use to be a great turbo for road racers especially for the power than your looking for. Maybe theirs a newer turbo on the market that can deliver what the rx6 use to. fast response and good power band.

Zero R

iTrader: (1)

We ran a 58/65 here and it seemed nice, though you will be asking for limited power numbers with moderate boost. Meaning expect around 350whp, with 400whp near the top. I would not run the 62mm turbine unless you use a 1.0 it will keep you closer to 300whp than 400whp with a .8 T/H. However If you're only after 330whp than maybe the 62mm wheel would be fine with the smaller .8 T/H. Also running a divided .8 housing on the 62 wheel means running a crap cast housing from a separate supplier that is larger and heavier than it needs to be. If I were to choose a Garrett I'd say run a either a To4E BB unit, a 35R with a .82 T4 "inlet" would limit you like the 62 wheel with a .8 T/H to that 330whp area but it would be very responsive. You could also consider a TiAL housing on the rear. We've made quite a few of those for the tight road course guys and they really liked them. They also seemed less restrictive than the .82 T4 "inlet" are simple to install and lightweight. If it were me unless you're on really tight technical tracks I'd shoot closer for the 400whp mark and turbo to suit. The engine will breath better, the car will perform better and you'll be happier overall. When you shoot for 350whp or less it tends to choke things up and create more heat than is necessary on the track which over the long haul will add to more maintenance.

~S~

BLUE TII

iTrader: (9)

I would suggest running a large exhaust wheel (balanced in relationship to compressor wheel) in a large AR but small frame size exhaust housing with giant turbo back exhaust.

Small frame turbine housing provides high velocity exhaust to a large diameter wheel exerting good leverage to spin the compressor wheel at low engine speeds and then the large wheel area and AR do not limit flow up top as much as a small AR/wheel combos do.

The giant turbo back exhaust is needed though to keep the pressure differential high for the low rpm spool.

I would do the 57 trim t04E ball bearing with uncut "P" trim exhaust wheel in the divided 1.00 T3 exhaust housing with a 4" turbo back exhaust.

I am interested in trying the "Q" trim exhaust wheel the divided 1.00 T3 housing to see if the effect is cumulative or if it drops off at some point.

Your only issue would be boost creep-

If you use the FD cast divided T3 manifold- you will have to port the waste gate passages/entry. If you use a tubular manifold it will have to be a good design with flow directed into the waste gate passages.

If you will be running 20+ psi boost anyways the boost creep is not an issue.

ScorpionT

iTrader: (3)

I agree the .84 divided housing is a bit on the small side for 350+whp, but the divided turbine housings are made by the same foundry as the Precision housings.

renkenkyo

iTrader: (6)

The main reason for having less power is to keep the car more planted. I find that on the road course I often do (Streets of Willow in CA), that the car tends to get tail happy. As far as running a GT35R, doesn't the spool time really hurt you during transistions?

Zero R

iTrader: (1)

I was reading this and thinking wow this sounds just like me when explaining running a divided .8 T/h on a GT3574. A turbine wheel is pinwheel, having a large volume of air flowing around in a larger volute will be less air driving the pinwheel. We found having the larger discharge of the larger frame wheel in the smaller A/r offset the most if not all the useable gain over the larger volume A/r with a smaller discharge. It's easy when think it is the job of the turbine to transfer the energy to the compressor and get the air out as quickly as possible. Tighter area around a larger wheel with a larger discharge loses little noticeable response and allows the air to waste no time driving the turbine. I found 62mm turbines with 1.06 T4's offered almost nothing over 65mm .84's as far as power and response between shifts felt much better with the larger wheel in the smaller housing (65mm .84)


That may be but they are no where near the same as far as casting quality, they are larger and heavier overall.


I think the turbo's needed response time will vary depending on the track you're at. I am not familiar with running a 62mm turbine on that track but I know that I have customers who are autocross guys and they run the 1.02 TiAL housings on the 62mm and like what they get. Are you ever really below 3500rpm much? If not I wouldn't worry too much about it. If your set on 350whp or less then stay nearer the 62 or even stageIII wheels just know that your manifold will run hotter and they will start to drop off over 6700rpm.



~S~

renkenkyo

iTrader: (6)

I suppose what I'm looking for is as similar characteristics to the 99' spec twins at APU (~340) with the reliability and heat reduction of a single. While I understand that I won't get the exact response of the twins, I was hoping to get as close as possible. I was looking at the GTX3076R but it seems like the turbine DIA at 60mm 84 trim might be a bit small. Is there anyway to customize this? Or maybe the GT35 is a better base to start from?

ScorpionT

iTrader: (3)

The divided housing inlet geometry is different, so it requires a larger housing. That also accounts for the extra weight. Ive had them side by side (several times) with PTE housings and found there isnt all that much difference in quality. Ive never seen any problems with the divided housings as of yet, and I know guys that run them hard. In terms of quality, the housings are very close to Precision and Garrett housings, but they are all blown away by Tial and BW stainless housings.

Zero R

iTrader: (1)

A 3076R is small to run on that car if you're going to run as close to twins as possible while getting the benefit of a single I wouldn't go much if any smaller than 62mm, the stage III wheel is 61mm and it can work but the 62mm Gt wheel just flows better. You could run a divided T3 1.06 or a undivided "T4 inlet" .82. Every kit I have sold with the undivided "T4 inlet .82 were to people who wanted response and weren't worried about power. They all landed in the 330 to 360whp range. They all said it was very responsive and very happy with it. While I think the T3 divided may be nice or even the TiAL housing as well. The benefit of this route is if the day comes you want more you already have a T4 manifold to work with. Although with the TiAL you can still step up to the 1.02 which will put you in the low 400's the T3 manifold will be very limiting even on resale if it came to it.

All I'm saying is, it's cast thicker it is heavier by far, also more along the lines of a 1.0 divided dimensionally when you compare it to a P-trim casting or even Precisions divided 1.0 housings which are very well made. As far as quality the it would probably last as long or longer it's just a rougher cast housing as far as finish is concerned. Garrett and Precision should step up to the plate on the stainless housing thing. Though Garrett does have TiAL in it's corner.

~S~

BLUE TII

iTrader: (9)

To OP-

My turbo on mild streeport (as early opening as possible and stock closing) did 340RWHP+ @ 12psi boost w/ 280+ ftlbs from 3,400rpm (full boost threshold) to 7,000rpm where it starts to taper.

I have a freeway on ramp I test my cars/set ups on. 2,000rpm roll on in 4th when I pass the paint lines to get on freeway and check speed when dotted on ramp paint runs out on freeway. 1:1 4th and 4:10 rears in my 7s.

My single turbo hits 85-90mph and my stock class sequential FD hits 85mph.

My single is stock S5 TII hybrid w/ T04B 60-1 compressor, "P" trim exhaust wheel in that ~T25 sized exhaust housing and a 60mm external wastegate.

Regarding your rear traction. I had a terrible time putting the power down until I changed up the suspension and now it has so much traction I can full throttle right off the apex in 2nd.

Use dampers with little low speed compression damping- not digressive damping like stock class cars need to control body movement on stock springs. Use linear damping curve and a little higher spring rate/swaybar setting for chassis balance.

This will allow the car to squat and transfer weight to the rear tires on acceleration. My car squats so hard/fast it looks like invisible foot stepped on rear bumper. It tends toward very slight power on understeer due to lifting inside front tire, but that generally keeps you right on the line and way out of the pucker factor of power on oversteer at higher speeds.

renkenkyo

iTrader: (6)

I figured the 60mm wheel would be too small. Sorry for asking a noob question but what are the benefits of a TiAL housing?

Is this in your FC or in the FD? I'm currently running Tein HA's but they aren't very good. I'm currently looking at the Quantum's that are sold through RE-A but still doing some research.

ScorpionT

iTrader: (3)

Yeah, it is a bit thicker than necessary, but if one bought the housing and was really concerned about the extra weight, the housing could be shaved down. The .84, 1.00, and 1.15 housings use the same outer dimensions, but the inner is different. That means the smaller a/r could have more weight removed. Of course the housing is similar to a P trim/Precision 65mm housing, the turbine wheels are identical in size.

Yes, Garrett and PTE really need to step it up with the stainless housings. Im very surprised PTE hasnt released them yet, considering their focus is racing. Standard flanged housings in stainless would be nice as not everyone wants to modify everything to a V band setup.

Jobro

iTrader: (2)

You can make a GTX3071R with the divided 1.06 T3 or T4 housing work.

If you combine that with a pair of 38mm MVS or a 44mm MVR and a dump pipe that tapers straight up to 4" you can get very good response with not much of a downside in power.

Flow wise you are limiting yourself by staying small, and sometimes I think **** its so easy to make power I could have made 2x as much for little more $$, but what is a pain has been turning wheel horsepower into speed coming out of corners, or accelerating of poor surfaces etc.

I think an FD with a tight course size turbo would be a blast, my 1st gen is and the FD would be able to handle and use it better.

Of course you can step up to a GT3582R or even to the GT35 / T61 / p-trim custom turbo but you will be trading off power where you want it for top end you probably won't use unless you only drag race.

renkenkyo

iTrader: (6)

That's what I had in mind as far as road race is to keep the power low but have a much broader power band so I can utilize better as I feel the 7's weakness is low-mid range torque so going for higher peak power doesn't feel like where I want to go with the car. I want to keep it as balanced as possible. I'm also giving serious consideration to just getting the 99' spec turbos and then tuning those but I really don't like the extra complexity and heat.

ScorpionT

iTrader: (3)

If you wanted to go a little crazier with a billet wheel, spend a bit more money, you should consider the BW EFR 7064. 52mm compressor, 64mm turbine, should be enough for just over 400whp and spool quick too.

renkenkyo

iTrader: (6)

Would you happen to have any dyno sheets for those guys running the T4 inlet .82? I'm trying to compare some numbers at this point. For your kit the GT35R T4 kit, what turbine housing are you using and blade size? I couldn't find any information here http://www.a-spectuning.com/html/products/gt35r_t4.htm.
Thanks

renkenkyo

iTrader: (6)

I've thought about the efr but I'm afraid that the wastegate is undersized.

ScorpionT

iTrader: (3)

BW says the wastegate flows up to 40% of the compressor mass flow. Thats plenty for what you want to do, and for the 13B.

They also have non wastegated versions, its a 1.05 a/r.

BLUE TII

iTrader: (9)

Is this in your FC or in the FD? I'm currently running Tein HA's but they aren't very good. I'm currently looking at the Quantum's that are sold through RE-A but still doing some research.

FC. FD is stock class so Tripoint front swaybar to control body roll and crank the damping up and tire pressure up in the rear to control body roll and understeer and no power to try to put down anyways so the digressive damping is great.

Get a suspension that is quick to be serviced/valved in the US. If you have the funds for RE spec Quantums, I would think JRZ or Moton would be a much better choice.