Looking to make my final decision tonight on my new turbo. I'll be going with a precision 6262.. My question is what would be the best a/r on an s5 mildly streetported, all the fuel mods and pfc ecu..my goal is a high 3 to low 4 hundred bracket.. Trying to make this motor last and put down some good power on the street... The options are:

t4 .68
t4 .63
t4 .58

Anybody have any input? From what I've gathered a .68 might be too big I was thinking of either a 63 or the 58 for faster spool...

 

Forgot to mention exhaust: It's a 3" dp andcustom divided manifold all plugged to a pair of apexi dual n1s.

 

Turblown TD61.

 

I'm looking into buying a precision turbo because I get good prices on them and I have a friend who works closely with them, thus eliminating any customer service or product issues. Any input on the stuff I posted?

 

I wouldnt go with any A/R lower than a 1.0 on a rotary, certainly higher than any you have listed. You don't want a restriction in the turbine housing..... you want the turbo to breath, esp at 390+ rwhp.

 

.86 .96 1 a/r

 

Go for the 0.86 A/R. . .I'll see if i can get the vid of our customer's car up. . .

 

Really? That's what I keep reading but my mechanic is somebody who's been around for over 20 years, pretty much the king of circuit down here, very well known and respected in the rotary scene.. He tells me he doesn't see the purpose of getting " one of dem giant turbos, they are too big and take too long to spool up on de street. You wan something nice and of average size"..He recommends I don't take it past 375 on the 13bt because it isn't practical for street use and it isn't healthy for the motor.. Anybody have any input on this?I'll be tuning on 94 octane...(no meth, no racegas) The guy who's supplying me with the turbo recommends this one, he says similar ones are working well for other people in the honda scene and they spool up quick.. I just don't want to get something too big for the street.. Very responsive and good for everyday driving but able to make the power I want well...

 

Borg Warner for the win. Precision ::

 

What works on a piston engine may not be a good thing on a rotor so what works on a honda may be no good for your rotor. I am coming back to rotors after some time with piston engines. (most recently 4G63 evos) Really having to relearn suitable turbos. An evo would hardly spool some of the "responsive" rotor turbos. Most responsive piston engine street turbos will choke a rotary on the exhaust side. Rotors definately like bigger turbines and higher AR's. A smaller AR will assist spool but only to a point. Too small seems to choke them. A respoonsive turbo for say a 2 litre piston engine will be to small for a rotor.

Heaps on good info on this site regarding this. Agreed with one of the above posters that the turblown TD61 seems to be doing good things.

 

Anybody??I have to order this thing tonight

 

Some discusion here and links to other threads with further discussion....

https://www.rx7club.com/single-turbo-rx-7s-23/precision-6262-turbo-836192/

 

You've already been given good advice, but don't seem to want to listen. Best of luck to you

 

So I'll be going with the .82 ar precision 6262(62mm)... I'm looking for boost at 2500-3000 not 5.. This is an s5 t2 not an rew not looking to port it too much. My last motor was ported out to the point that one of my exhaust inserts melted and destroyed the engine.. Not looking to go to crazy with the porting I think this should be fine.. Correct me if I'm wrong here...

 

The only solid advice anybody has given me is to "buy a borg warner,buy a turblown, look at this thread full of people arguing back and forth about precisions quality control" or "rotaries love big a/rs" I keep asking FOR MY SETUP, FOR WHAT I WANT TO DO WITH THIS TURBO, FOR THE POWERBAND I WANT. What is a good a/r? I'm listening there are just too many people throwing different answers at me and I don't need a turbo that will only kick in at 5500 rpm. I may be coming across as an idiot but I have to get moving with this so Im trying to get solid answers. Apologies again to those that are being helpful.

 

a good a/r for what you want to do is whatever you choose based on the feedback you're giving to people's advice/opinions.

People did give valid advice pertaining to a/r but you are refusing to take it.

 

Be keen to hear how it works out. Looking for similar performance myself. 400whp max on e85 with the best response and torque I can get.

I like the TD61, but when I see it make close to 500hp I kind of think it has all this excess capacity beyond my needs, and having that capacity in reserve is costing me response and midrange. (I may be wide of the mark heer so feel free to correct me)

 

Hate to break it to you, but something like the A/R of the turbine is NOT GOING TO MAKE A HUGE DIFFERENCE, IE SPOOL AT 3000 VS 5500 RPM.

Thought I'd yell a bit since you seem to like doing it

Btw, do you understand what A/R is and what it means? www.TurboByGarrett.com has some good info in their tech section under 'Turbo 101.'

 

Exactly what I'm looking to avoid. I sense people are getting frustrated with my questions but I'm trying to get some very specific answers to some very specific questions. Some of the answers I got were as broad as .82 even 1.0 are "good on a rotary" because you don't want to choke the engine. I understand this concept, but the word rotary can describe anything. I was asking more in terms of what I'm looking for in terms of my setup.

 

Alright thanks for pointing that out to me I'll give it a good once over. Reading the part on a/r a year or two ago, it honestly started turning into Chinese after the first sentence or two, but now I know a bit more it might make more sense..And I assumed A/R made a big difference because people make it out to be one. BTW I also wasn't trying to yell, I was attempting to make that little part stand out more. Apologies again.

 

If you want a better spool it's a good idea to have a divided inlet and to keep the a/r "smaller". It's such a vague statement as you really need to look at the turbo as a whole. Relation from the compressor wheel to the turbine wheel is crucial. I still maintain my statement I posted before but you seem to be a blind believer like "Neo" in the matrix. Goodluck...

 

What I think your doing is trying to harp on me for amusement or points here on the forum. I think I've already stated 40x that I will be buying a Precision product.i understand you prefer Borg Warner personally but I have a good connection on precision for price and service. From what I've read and what I've seen they seem to be doing well for a lot of people so it makes no sense to go with anything else. If you were commentinv on the turbo or a turbo within that brand it would be more helpful. I appreciate your input nonetheless.

 

Those are Honda a/r's you got listed. Definitely have to go much bigger like GoodFellas said above. I got a BW S366 and as big as the cold side is the a/r is still .91.

 

I'm not trying to harp on anyone here. I'm trying to save you money and time. If I had permission I would tell you a nice story about Precision turbos, though I can't. I'm not trying to start a pissing competition but I have a lot of experience with with turbo's of all brands. I'm not someone that's bias and sticking to something that I only have experience with.

I don't care if I could get a billet setup for $600. Their quality is equivalent to ebay; this isn't an opinion of mine just a direct observation in person with more than one unit. You wanted advice, I'm giving it to you. If want AR advice I'll simply say go with something in the .8-.9 range.

 

From what you are asking it sounds like you are looking at simply too large a turbo for your target power. A/R isn't going to change spool/boost threshold rpm that much.

I would guess you would be better off with a compressor inducer around 53-58mm inducer and a slightly smaller turbine than the 62mm exducer to get your lower boost threshold/response.

What people are telling you is right, run a really tight A/R on a turbo which is already a bit lop sided front to rear is asking for something that is inefficient across its entire operating range, slower to spool than a smaller turbo and won't make the power the wheel sizes suggest.