Turbo sizing

[JPO8GT]

I have searched but cant find any threads on subject if the info is on here please post link.
Im trying to find proper size single turbo capable of 1000-1100 RWHP through my 326 ci 3 Valve. Im looking for a unit that will be capable of solid power to 7000+ with minimal lag / spool rpm. rpm shift points at 7400 -7500 with best bearing technology for quicker spool. Also will be using custom turbo grind cams.
I have been trying to locate compressor maps on some precision models but haven't found yet. I'm new to turbo research but want to learn for future project.
Im also currently researching twins but do not want twin turbo setups to be part of this thread. So medium to large single turbo setups only please.

 

[TurboX]

I similar goals in mine, I just started the car last week and hopefully will begin tuning.

Before I give my 2 cents, what are your intensions for the car ? My car is street driven to play on long deserted Texas roads, I also want to do 200+ in the Texas Mile.

I have a Hellion kit that has minor modifications, waste gate vented to atmosphere and changed from suck thru mass air to blow thru. To compensate/supplement the standard air to air intercooler I plan on using a Snow performance stage 2 meth kit. I am unsure of the percentage meth/water combo, I will leave that to Lito. My last combo made 800RWHP on 18.5 psi, I had a Turbonetics 76mm .96AR Q trim with BB. This was made on a 323 with stock heads, Ford racing intake and custom cams by L&M.

My new combo is a 322 RGR, JPC intake, JPC super duper heads and RGR cams with a PT7675 BB. I personally do not believe this Turbo will make the 1100RWHP you are after, PT rates it at 1160HP but JPC has said they made over 1200RWHP on a Coyote. You might want to look at the PT7685, I believe PT rates it at 1400. I am not going to be able to report back because Lito and I will be taking baby steps, hopefully in the next few weeks I can say what kinda power I made on 11 psi.

Good luck, this kinda HP is easier to make on paper than it is keeping it together.

I am also on a 10:1 motor and E85

 

[JPO8GT]

My intention is some street driving 1/4 mile drag with a little 1/8th mile drag.
At this phase
Jpc/RGR will be converting my boss block to 6 bolt main and going to billit steel i-beams they are also looking at cryo treating the block,crank & i-beams were also looking at rgr upgrading my ford racing big valve heads to include the high temp valves heavier springs single grove locks basicly upgrading them to rgr stage 3 to withstand the additional exhaust pressure that turbo creates.
I will be adding to my 6 point to make it legal to 8.50 1/4 mile.
So in planning stage for all this now.
Basically I'm taking the car as far as the stock pcm will allow rev limiter is 7750 rpm max if you want more rpm than that its time for Big stuff 3 or Fast ecm setup.
I will run less power on street tune 93 and i have a 2 jet aem meth system with progressive controller i run 50/50 mix on street. At max power race tune i run vp c16 race gas.
If it don't stay together it won't be because we dident use the best parts.

 

[CPRsm]

You're going to be looking at a GOOD 76-80mm and 80-88mm turbine. The sizing is going to depend on what shaft speed you're willing to give up for spool. I'd honestly start w a small T6, and a 5in down pipe if you can fit it. I wouldn't worry too mich about spool on the street w an auto.

 

[michael.konor]

No matter what size you get, make sure you spend the extra $$ and get a Ball Bearing setup instead of journal bearing. My car wakes up so much quicker with BB than it ever did with a journal.

IMHO, well worth the additional cost.

 

[LTHLCHRG]

I am shooting for the same power goals.i have gone with a 8484 comp turbo,and have been using Jeostangs car as a guide.

 

[JeremyH]

76-80mm ish size if billet wheel, 88-90mm size if going cast wheel. I would reccommed a billet wheel myself and bb for sure. .96 to 1 ish for ar and 3.5" to 4" vband outlet on the turbine.

 

[TurboX]

Jpc/RGR will be converting my boss block to 6 bolt main and going to billit steel i-beams they are also looking at cryo treating the block,crank & i-beams were also looking at rgr upgrading my ford racing big valve heads to include the high temp valves heavier springs single grove locks basicly upgrading them to rgr stage 3 to withstand the additional exhaust pressure that turbo creates.

That is my combo as well minus the cryo, it sounds like your goals are possible but like CPR states. Its going to depend on what you are willing to sacrifice, big end power will cost you on the street in spool time.

My initial impressions of this PT7675 are that it does not spool as fast as my last Turbo. That could be because the car hasnt been tuned, this Turbo has a bigger exhaust wheel or that I have rerouted the waste gate to atmosphere. I knew the bigger wheel might cause the spool time to increase but thought that the bullit wheel might offset that. I have run across a few threads saying billet wheels are the latest snake oil of Turbos, apparently a Billet wheel is also heavier which also increases spool time.

Good luck on the build, I look forward to reading about it as it progresses. I will shoot you a PM once tuning progresses and boost goes up.

 

[CPRsm]

I am shooting for the same power goals.i have gone with a 8484 comp turbo,and have been using Jeostangs car as a guide.

You'll need to go pretty large on the AR. IDK if it will make that power with that power if you you went T4.

 

[JeremyH]

He went with a CT5X 1.25 ar/4" irrc. Will easily make 1000rwhp. It also an extended tip billet wheel impeller.

Me want! lol
http://www.compturbo.com/spotlights/extended_tip_compressor


Turbopete was running 950rwhp with a billet 74mm in a t4/3"vband config and guys do it with the billet 76 quite often.

 

[CPRsm]

I know the compressor is capable. That's not what he'll have to watch out for. Just need to keep an eye out.

I have run across a few threads saying billet wheels are the latest snake oil of Turbos, apparently a Billet wheel is also heavier which also increases spool time.

Yep, it can be snake oil. Totally depends on how it's done. Some companies will make the same shit but in billet. On diesels that is ok, or in the import world where there is a shit ton of boost and the stronger billet will deflect and deform less. But the 80mm we'll be playing with is 50 grams lighter than its cast partner. Testing showed another 5psi capable than cast and made a shit ton more power. But it was done right. The 76mm has the same hub to fin length at the cast 80!! Some will copy cast though and sell as an upgrade, and there won't be any benefit.

 

[JPO8GT]

Many choices when it comes to turbo my personal desire is finding the one properly sized for 326 ci and thats great boost producer from 3000's- 7000+ rpm Ball bearing is probably a must for single. From my understanding the 326 ci is better at spooling quicker than stock 281 ci sounds like i want my cake and eat it too and its true. But can this be done with a single and have 1100 rwhp capability on big end and have better bottom end than a centri without having to launch at 4-5000+ rpm with trans brake im trying to keep launch between 3000-3800 max on tbrake due to trying to keep some street in car converter wise +less heat on trans Hummmn i am curious if this is a tall order for a single turbo but technology has improved since i last researched turbos 10 years ago.
I have had 2 pd blowers and now a centrifugal i like both the pd blower hits hard on bottom but goes flat up top i love the way the centrifugal pull up top and seems to not stop i like the feel of the centrifugal and it seams more controllable on street than a heavily wicked up pd and to me the heavily wicked up centrifugal would be my choice if i had to chose between pd and centrifugal only but now there's still turbo that i haven't tried.. Can i have a little less hit than a hard wicked PD on launch but harder hit than centrifugal some where in the 3000+ range and solid-hard pull too 7000+ shifting at 7400 -7500.
I think i can.
This to me would be best of both worlds.
Thanks for all the info everyone please keep it coming. Once I'm done i plan to know the pros and cons of pd, centri & turbo and i will be able to say i enjoyed doing it i can already vouch that forced induction is good no mater the form you use. I know twin turbo setup is not part of this thread but if my research finds that i cant achieve what I'm looking for in a single i will then result to a twin build single just seems more challenging that i like.
Jamie

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[JPO8GT]

Currently looking at Single Precision 6262, 6266, 7675, 7685 & 8285 now got to dig into details.
Any one with real world experience on any of these 5 or similar spec units from other manufacturers please post.
Ohh hell this book showed up yesterday hope i learn something. Lol... In the current time going to track with the novi wish me luck should see 9's ran a 10.0 137 mph on 93 meth street tune shifting @ 6500 still working on 60ft launch only 5ish psi at 3000 this time itll be on Bobs race tune c16 shift @ 7000.

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[CPRsm]

I'd stay away from Precision personally. I've had entirely too many problems with their stuff. So much so I won't sell any more GT500 kits until I switch them to a single. And a big reason I didn't go w twins on the coyote.
You goal is attainable w a single no problem. Our guy has done 1297rwhp from that 80mm I was describing and is working on an 83mm lol
You'll still be looking at a 4k+ leave rpm either way. The way it spools will be cam and converter setup. Depending on when you EVO is is where you'll start to make torque, or if it will make power at 7k. When you start making big power you want to advance it, but that gives up work on the piston that creates torque.

 

[JPO8GT]

Im not stuck on precision just seem to here the name alot maybe fluff if you know what im saying. Required maintenance on the unit is also important thats why im not sure on some styles i would like little maintenance on the turbo it self although im a oil changing trans servicing crazed maniac.. Lol.. And as far as launch rpm im probably being in conservative side the truth is if i went by my centrifugal power curve id have to launch at 5+k to be optimum because tq is there but it peeks 5500+ up in curve. 4 k sounds good to me.

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[CPRsm]

Shut down time after beating on it helps a lot. Keeps the oil from cooking in the bearing section. Rpm just won't be needed on a turbo, torque comes in sooner. You'll more than likely find yourself pedaling for a given boost level or using the controller to do it. I could vary mine from 7-14psi in the range of 3-3400rpm. Yours will be a touch trickier with a larger turbo though. If the kit is easy to work on I've a few swap housings befoe a race to HUGE. Then put a moderate on again later for the street.

 

[TurboX]

Currently looking at Single Precision 6262, 6266, 7675, 7685 & 8285 now got to dig into details.
Any one with real world experience on any of these 5 or similar spec units from other manufacturers please post.
Ohh hell this book showed up yesterday hope i learn something. Lol... In the current time going to track with the novi wish me luck should see 9's ran a 10.0 137 mph on 93 meth street tune shifting @ 6500 still working on 60ft launch only 5ish psi at 3000 this time itll be on Bobs race tune c16 shift @ 7000.




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I can tell you that the 62XX will not cut it, look no smaller than the 7675, personally opinion is the 7685 would be best of your units listed.

I'd stay away from Precision personally. I've had entirely too many problems with their stuff. So much so I won't sell any more GT500 kits until I switch them to a single. And a big reason I didn't go w twins on the coyote.

So I know what to look out for, please explain. I bought my Turbo over a year ago, any problems will probably be on my dime.

 

[CPRsm]

Anything really. Compressor or turbine touch touchdown or complete lock ups. Compressor nuts coming loose, ball bearings inside the turbo rusting. Every single turbo I have sold except 3 have failed. And one isn't running yet that I know of. Some of them have been rebuilt up to 3 times, and a few of them were charged for a rebuild while under warranty because it wasn't "Presicion's fault." Last straw was a week ago when I found out my customers ball bearings in his turbo rusted, for the second time. The first rebuild was from the turbo locking up first pull on the dyno. Their reasoning on the rust was he washed his car and put it away wet.

 

[JeremyH]

I went through three precision turbo's in a little over a year including a compete rebuild of two of them(a cast PT6776 and two cea 6765's) they were all journal bearing though. I have heard of the rusting issue with the steel bb units as well, not saying they aren't good capable turbos but I had bad luck with them. If your looking for low maintenance for a 1000rwhp track car turbo might not be the best option for you. If its oil fed your looking at getting it serviced at least once a year.

Ceramic bearings is the better choice imho, less heat and friction, better high speed stability, less bearing deformation with heat, no chance of rust etc.


A properly sized single billet bb turbo will spool just as fast if not faster than smaller twins contrary to popular belief.
You have the whole volume of the motor(all 8 cylinders) feeding the one turbo vice splitting it and having half the engine feeding a turbo on each side.

 

[MRSUPRA]

I've had 4 different Precision turbos on my Supra, 3 JB, 1 BB. Never had a problem. And when I pulled them off to sell them, none of them had any execcive shaft play.

I personally feel that BB is a waist of money. Had 2 turbos nearly the same size, and the spool difference was not noticable, not even the transient response between shifts.