Twins for 5x20's

[mike8061]

Well have been thinking alot about it and have decided to go with the 5x20s with 14mm and try to get enough air for them.

So i'm thinking 362 with .83 A/R and a 475 1.1A/R with a 45mm EWG bypassing the 300.

for the rest of it i will be going with 3rd gen intercooler. Modding some sort of 3 inch elbow on the intake. 188/220 Hamilton cam with there springs and push rods. Head studs with a copper gassket and .004" stainless rings. ( dont have a near buy machine shop I trust with machining for O-rings so i'm going to try the copper first and see from there)

In a few years when funds recover I will get a hamilton head with the intake choped off and ported.
My fuel system plan is outlined in the fueling solutions for VE thread.

So the question is do you think these twins will spool low enough to be usefull at VE rpm's and will they flow enough for 5x20'S

I debating about going to a 364 but am afaid it might hurt spool to much.

[oldestof11]

There is no reason to go bigger than 60mm on the secondary turbo unless you are pushing more than the VE can currently do.

To size properly, you need a crap ton of math done. No matter how much I input numbers, a good HX35, Super HX40, or similar sized S300 will be best for compounds.

[mike8061]

Think i could get away with a S300-58? with a .73 A/R?

[JQmile]

Looks like a good setup. Don't know much about the copper stuff, but other than that, the injectors and turbos should work. A 75mm should support 800rwhp. Looks about the same as my setup, only with another turbo instead of a huge shot of spray.

[mike8061]

JQ how did you find the 62/65/14 for spool with the 6x16? Its says in your sig it says dual waste gates, are these both external and what size? Was one not enough to keep the drive pressure down with that huge shot of spray? I'm leaning towards a 62 with a 12 or 14 for spool but if I need 2 external gates it would be nice to order the manifold with both flanges installed.

I'm planning on a turbosmart ultagate 45mm with a gated manual boost controler set up to regulate drive pressure instead of boost. Anyone heard about the reliabily of turbosmart stuff? How much wear on the tubos do you guys think i would save with a BOV seeing as its going to be manual? wont be drag racing so loss of boost betwen shifts is not a big deal. Trying to let off the fuel slowly every shift to avoid barking the turbo's seems like a pain.

Ive done a fair but if research on the copper head gasket. The biggest problem seems to be sealing the oil and water passages so they dont weep. For less than 300 for the gasket and the wire o rings i'll give it a try. I'm building the motor out of the truck over the winter so it will likly be summer before I get to try any of this stuff out.

[Tacoclaw]

I've got a 38mm external 'gate dumping into my downpipe to control my total boost, and it holds my setup at 50psi right now with no sweat. S362 over S475.

One thing to mention, is make sure you've got a good boost controller going to your external 'gate. There's no such thing as a small leak on a 44mm hole. My boost controller doesn't seal perfectly and you can really watch the boost slow down when that 'gate cracks open.

[mike8061]

Ok so a 44mm would be 34% larger than a 38 so sould be more than enough.

The boost controler im looking at is basically just a regulator. It just limits the pressure going to the gate. Its mounted in the cab so should be fairly easy to tune. Just keep turning till it allows the boost you want. Probably a good idea to have a passenger adjust while watching the gauge... I just realized im going to need alot more gauges

Drive pressure
Primary pressure
Fuel pressure
Case pressure

Already have water, trans, pyro, boost, tach. Think of any others that would make tuning this setup easier?

[dvst8r]

What turbo is currently on the truck?

[mike8061]

Right now its a short block on the stand. Had stock with good leak in the intercooler. By the end it could barly make 15PSI lol.

[shiftycapone]

A stock gasket and o rings is way less than $300, so why not find a good shop and not worry about seeping fluids? Or good studs and stock gasket, held 75psi for over a year on my 24v, and the failure was my fault when the gasket did let go finally.

[mike8061]

Ive been considering that. Will likly put in the stock head gasket with studs first then try the copper one if that fails

So far i'm at 57/71 or 68/.83 and 78 or 80/92/1.1 for turbos. thoughts on this setup?

Im going for maximum spool on the secondary. if the 57 proves to restrictive on the top end ill swap in a 62. I have read about severall 1000hp trucks runing 56-58 secondarys without an issue. so im thinkin 600 should be no sweat.

[oldestof11]

The key to not choking out is wastegate tuning.

[mike8061]

Yes i'm not worried about choking the hot side. Its the 78 or 80 primary compressor trying to shove 130 pounds of air a minute through the 57 secondary compressor that some people feel may pose a problem.

May causre a fiar bit of P/R imabalance on the top end but i'll be tuning for mid range for the most part. If the primary get pushed hard a few times a year i can live with that. Most of the bearing failures Ive read of on the 400's are due to the high pressures when running them as singles on 6.7's