turbo sizing

[jjump59]

also need some help with selecting two turbos that will work for this deal. i have a stroked 400, 461 cubic inch, max rpm 6000, maybe 16 lbs of boost max intercooled and fuel injected. i can provide any other information you might need.



so many choices out there, i just keep getting more confused. i'd like to get them as cheap as possible but it's looking like i'll just have to spend the money. thanks for any help you can provide.

[Y-TRY]

I chose Precision Turbo's PT-52 turbos based on a couple VERY successful builds: Monty's Corvette , and John Meaney's Corvette. Give them a call, but I think you would be happy with the same.

[Matt]

If you wanted to watch your price you could get two big 16G's or 18G's, good odds you could get both turbos for 800(16g's) to 1200(18gs).

[andrewb70]

If you wanted to watch your price you could get two big 16G's or 18G's, good odds you could get both turbos for 800(16g's) to 1200(18gs).

More info please...what is a 16G? 18G? who makes them? are they take offs?

Andrew

[Matt]

Mitsubishi turbos, they are both thurst bearing normally, but I think ball bearing variants are made of each (not 100%). 18g's are externall wastegated, 16g's come internally and externally gated. I believe the twinscroll variant of the 16g is what comes stock on the mitsubishi evo 8&9. Pretty dependable, but they use a non-garrett type flange. Twin 18g's (pretty normal ones as other variants from different turbo houses can be made to flow more) should be good for up to 700rwhp. 16g's should be good for 550-600. They are quiet easy to source as well.

If JJump had a hp goal it'd be easier.

If you got them from the same source you could do twin t3/t4's which a pretty mild one (since t3/t4's come in so many variants) would be good for somewhere around 750, maybe 800.

Or if you really want cheap some of the smaller holset turbos work too, though they are pretty archaic design, I've seen some 9 second cars using the bigger holset singles.

If you had a 350 built for boost, and you really wanted cheap you could go with 13g's which could probably do 500-550 horse, and spool stupidly fast. You can get 13g's for next to nothing, but I'd say twin 13g's would be better suited for a smaller motor in the high 200cid range.

When it comes time for any of you guys to purchase turbos I have buddies at AGP & a turbo kit maker that does the stuff for the new Shinoda cars and I could surely find you a deal on something that would work.

[Matt]

General rule of thumb, take the turbo's cfm x .7 = about how much hp it can manage.
or take the hp you want x 1.5 to find the cfm's you need. These are easy numbers for me to do in my head, which is why I use .7 and 1.5, depending on so many other variables to get real numbers so there is of course a margin of error.

Just for giggles here is a twin 88mm 700ish Cid mustang that was making over 1000hp at 3psi and 1800 at 11psi

[jjump59]

cool picture, what i'm hoping for is 800 hp normally with the ability to crank it up some if needed. Max of around 1000. Those turbo's seem to small for what i want to do especially considering the 461 cubes. thanks for the input.

[Matt]

Well, we all have different goals, since a lot of the guys on the site kinda frown upon stuff over 600, I figured I'd shoot for something more moderate.

Twin 20g's would do the 800-900 mark, and they are reasonably priced as well.
Twin gt30's could let you hit 1000hp, and they would spool quite nicely too, but would be maybe $200 or so more each.
If you want to have a really nice setup with some room to grow gt35R's are really really nice turbos as well, but ball bearing and cost umm, double a gt40 which will get you the same power.

My personal experience ball bearing turbos are cool, and spool a few hundred rpm's quicker, friends did a test of an IHI vf34 vs and IHI vf39, same size, the 34 is bb, and spool was like 200rpms quicker, which is a joke for the extra 300+ dollars.

As for boost controllers.... Some people swear by greddy profec B's, I think they are a hassle, and real pieces of junk. The only electronic boost controller I've ever really fallen for (unless you are gonna use a fast to control everything) is the Blitz SBC-ID, it works amazingly well on twin turbo apps.

edit: Oh yeah, go with cometic head gaskets, they are worth their weight in gold.

[shearer]

18g's are junk. We've ran them before and have alway gone back to the 16g and have run better. This is the DSM'r in me speaking out. With either twin 16g's or 20g's on a 460" motor they would need the 10cm t3 flanged housing with a good clip on the exhaust wheel to keep back pressure down.

The EVO 16g's are surprisingly efficient turbos. They are a reverse rotation turbo but there exhaust side is way to small for a 460" motor. backpressure would be through the roof and it would prove difficult to control shaft speeds with the little internal wastegate.

Twin GT35r's with a t4 housing would be an awesome choice but very pricey. $1350/ea my retail. A customer of mine recently made 668hp on a 122" motor with a single gt35. Twins on a 460" motor would easily net 1200hp in the mid 20psi range with a good set-up.

If it were me I would slap twin 60-1's on it. They are a good low pressure turbo that can support 500-600hp each depending on wheel and housing selections. They are relatively cheap, common, and are now available with a newly released ball bearing CHRA from Garrett. I ran 128mph in my talon, which weighed 3400lbs, back in 2000 with just one of these.

[Matt]

See, I've seen good numbers for all sorts of cars with single and twin 18g's, so I'll disagree with you on that. I didn't know that about the 16g's, but I do know they are good turbos. One of my friends just put a gt35r on his mustang, and is putting down about 600, too much more and it'd be overkill for the car. 60-1's are a good choice certainly.

[shearer]

We have got the 18g to run pretty good also, maybe junk was a harsh word. However we have never managed to get an 18g's to run faster than a 16g, very similar numbers were obtained though. On the street the 16g proved to be a lot more fun with more midrange and faster spool up.

[Matt]

I've never done a comparo test, so I'll take your word for it. Living at over 5k feet, and my biggest turbo experience (for the smaller turbos) being wrx's, I don't know what timely spool is ;) (for those that don't know the setup on wrx's is stupid and the turbo is a good 1.5 feet from the exhaust ports on the motor.)

But to the point, there are a million turbos that would do the job well, and between shearer and I, you should have a good idea what will work.

Also my buddy made 900hp on a twin turbo 4.6L mustang cobra with two 60 trim t3/t4's

[ty1295]

I think twin 18g's would be fun on street, from stop but limit your top end. IMO.

I have a 350 here with twin GT35's (not the R's) Called up precision turbo told them what I wanted, etc and they custom built the housings to match.

Got twin Tial wastegates also.

I get dealer cost which helps, but was still a chuck on change just in turbo's and wastegates.

[jjump59]

i see that the 60-1 come in a few sizes, am i right in guessing i would want to stay with the larger ones? they show a .68 and a .96 or something like that. what is a super 60-1? one of the venders had thta one listed for $599.00. what size wastgates would work? thanks for the help guys, can't wait to get started.

[andrewb70]

18g's are junk. We've ran them before and have alway gone back to the 16g and have run better. This is the DSM'r in me speaking out. With either twin 16g's or 20g's on a 460" motor they would need the 10cm t3 flanged housing with a good clip on the exhaust wheel to keep back pressure down.

The EVO 16g's are surprisingly efficient turbos. They are a reverse rotation turbo but there exhaust side is way to small for a 460" motor. backpressure would be through the roof and it would prove difficult to control shaft speeds with the little internal wastegate.

Twin GT35r's with a t4 housing would be an awesome choice but very pricey. $1350/ea my retail. A customer of mine recently made 668hp on a 122" motor with a single gt35. Twins on a 460" motor would easily net 1200hp in the mid 20psi range with a good set-up.

If it were me I would slap twin 60-1's on it. They are a good low pressure turbo that can support 500-600hp each depending on wheel and housing selections. They are relatively cheap, common, and are now available with a newly released ball bearing CHRA from Garrett. I ran 128mph in my talon, which weighed 3400lbs, back in 2000 with just one of these.

Where do you buy 60-1s with BB CHRAs? Do they offer 62-1s with the BB CHRAs?

Andrew

[shearer]

I sell them as do a bunch of other shops. I get all my turbo's through Precision, so pretty much any Precision dealer will have them also. There are 6 or 7 different turbos available in BB now that utilize the older style wheels. Also remember that these are Garrett BB units and not the dual BB units offered through Innovative and a few other turbo places.

I don't remember off the top of my head whether the 62-1's are offered, I never had luck with that turbo anyway.