morkable

Hey Mike, talked to Glenn at ED tonight. I am going to send my wastegates in to him. He was suprized that I am even running them on my truck with those turbos. He suggested also that I should look into get a bigger turbo on the bottom.. what can you get a s500 turbo for?? and what size housing?

I might try to sell the wastegates, and the 488 and buy a s595 or 510 turbo

Tate

You might want to down size your secondary too. Do a shot of spray between stages for the cooling effect, and you can get away with a smaller turbo, should spool quicker. Thats assuming spool is a concern for you. A S595 is around $1900.

Mike Holmen

They start at about $1900 and go up from there depending on what you want. I'm trying to get all the build specs and different housing sizes that are available for that turbo. I'll post them later on what we find out.

I could probably work out a deal on your old turbo. As for the gates, you'll still need at least one gate. I would run that existing secondary just to see how well the truck spools, as you do have a 6.7L. Its is easy enough to down size some on the secondary like Tate suggested but I would do some pressure measuring to see what you need.

I ran that old GT4202 on the weekend in the lastest twin creation, it actually works out pretty nice. We intially drove around town almost all on the GT4202. We had around 25psi of boost, 15psi was from the primary. Used an adjustable boost controller, now we are over 55psi and the primary is around 25psi.

I would stay away from ED turbos. I would say more but...

Doj Dewd

i would stay away from ED as a whole. the service was less than desirable . . .

i also heard through the grapevine that they buy someone elses gates and just put 'ED' on them. the company they do this to gives even better service when issues arrive than ED (even when buying an 'ED' gate). i don't recall the original manufacturer of the gate though . . .

morkable

Yes they do buy another companies gates. After talking to both Glenn and Ryan Bean, they were both of the thought that with turbos that big wastegates would not be necessary. Even with spray. But I might keep one then, seeing as I have all the gear anyways. I think that depending on how big a s595 is I may re engineer my whole twin setup anyways. Let me know what you find out Mike.

PS, who knows how to lap valves?

Lil Dog

What did you find with your head? Warped valves or just not sealing?

morkable

head is fine. These are the valves on the wastegates

Lil Dog

Ok.. Well that shouldn't be tough..

dvst8r

It has been (what I thought to be) common knowledge for quite some time that ED gates are JGS gates. Jgs makes a good USA made gate, and I am sure the gate ED buys from them are no different. My problem with how ED gates are used is that the exhaust flow needs to turn 90* in a short time through a small hole (in their adapter spacer plate). From a flow perspective it is setup to fail.

Kevin, for your setup I would still run a gate between the manifold and the primary, so you are able to gate around the secondary's hotside. This will allow you to run a lot smaller secondary if you wish.

If you step up to an S500 chassis primary turbo, I agree that even with a LOT of nitrous, you still wont over speed a turbo in that chassis. To give you an idea both your S475 secondary, and the S510 are good for over 4:1 PR's which means you could still be in the efficiency island at over 200psi of manifold boost... That would be more then a wee bit of nitrous to push those turbos out of their respective maps.

One last thing to keep in mind. It is 100% the primary turbo that limits your total power potential. Total flow for a compound set is totally based off of what the primary turbo is capable of. Total PR and drive ability are based of the combination of the two chargers.

Mike Holmen

Good points Brett, the real trick is getting that primary to load up decently. Basically you use the secondary to get the engine to start making power, then you switch over to the primary (well sorta). At some point your secondary turbo becomes a choke point, but Kev, your a long long ways away from choking out what you have. Probably the only good thing about the S400 as a secondary you have a large frame compressor housing.

morkable

I really dont think I will have too muc problems lighting the 475 to be honest. Not with the fueling and the cam that i have in this unit

Tate

Not a problem with lighting it, but you could actually make that thing half driveable. We both know that a 75mm as a secondary isn't a quick reacting turbo. Its the same as running it as a single. Get a smaller secondary, and nitrous being needed for staging wouldn't be an issue.

Mike Holmen

Kev, if you build the twins correctly, a smaller turbo for the secondary, probably wouldn't hurt you're maximum power. You'll findout pretty quick if you what you need for turbo configurations. Changing that secondary for something different is pretty easy stuff.

Just a half dozen or so beers.

dvst8r

Even if you went really small on the secondary (I have a size in mind), and were aiming to keep balanced PR between the primary and secondary, most turbo's in the size I am thinking will still do a 3:1 PR giving you still lots of head room in boost psi... ~118psi manifold with it balanced at 3:1 each.

morkable

I think that I want to stay with the 475 on the top. and just go bigger on the bottom, remember guys I dont really drive this thing on the street. And I am aiming for total bullet proof. I feel that if I go with the bigger turbo I have much less chance of over spinning it and so therefore less chance of grenading it. The cam that I have in there was geared towards making this turbo spool good, That being said I am thinking that if I go to a bigger turbo I might change the whole configureation around.. I think I would put the big turbo right beside the altenator (somewheres around there)