Heads & Pistons?

[Terrible Buddhist]

As I mentioned, I am building a twin Turbo 580 chevy, I am planning to run between 15-22 lbs of boost. I already have the crank, Block & Rods, and am trying to figure out where I want to go for the upper end. Any suggestions on pistons and heads, compression ratios, etc. I would like Aluminum heads to make up a little bit for the extra weight of the turbo's. I am also most likely going to go with an Electromotive Fuel Injection setup. Thanks for your help....oh ya, this is going on a Jet.

[skijake]

Sounds real nice....
I use JE pistons myself. I find them top quality and built to take a beating.
JE Pistons is in Huntington Beach Calif, they also have a company known as SRP pistons
The SRP line (short for sportman racing pistons) is more for the bracket racers and super comp drag racers. Very good piston and less expensive.
The JE pistons are what most guys doing what you do use, all the way to top fuel for JE.
They make an excellent blower or turbo piston with a bigger distance to the top ring for quench. They are proud of their slugs so they do cost.
They have several on the shelve pistons that may fit your application. give them a call and they will work with you on what is best.
They also make custom pistons so if you do not see what you want just tell them.
Good luck with the project

[schiada96]

I replied on your outher post. My engine has a eagle crank and chevy rods that have had a lot of work done to them. I should have stepped up for good rods but no problems so far. SRP flat top pistons 4.530 for a 8.35 cr I'm running a rtp chevy steel head good for turbo power. Most turbo engine builders prefer steel for heat retention and weight is not that much of a concern on a boat. Turbos are turbonetics TO4's they spool fairley quickley for a draw thru application.
This was the first turbo motor I've built. The only advise I have is take your time and use the best parts you can afford.

[Terrible Buddhist]

the fact that you are making 17 pounds with T-04's is even more impressive, what RPM do they come into full boost? What kind of waste gate system are you running, and what the hell did Turbonetics do to those things!

[schiada96]

Right foot waste gate. They are un drilled housings. Rick Head did them he was the manager for years at turbonetics he recently started his own deal. We should meet sometime at the river and you can go for a ride.
Jeff

[ponponracing]

Sorry not to agree.
But you should use aluminum heads for heat dissipation, particularly with a blown or turbo application.
They absorb and dissipate better the heat that is transfered to them by the valves seats, and this is very very important when you talk about big hp, turbo and blower application.
Many years ago, people were talking about cast iron running warmer than al. but it's what you want to avoid with power.
JE is a good piston, Arias Venolia Speed-Pro
and whatever the brand are also good pistons as long as you know what to do with them, how to install them in your application, and that you ordered the right part for your motor.
If you want another plus for al. heads, keep in mind that in case of badluck, you mostly can have them fixed by specialised shop.

[DetroitJim]

I learned the hard way- do not run a piston with any type of notch or sharp edge near the exhaust valve. I made the mistake of using low cost TRW pistons with a chamfered crown, and since they are not right hand/ left hand pistons, the intake valve relief is mirrored to the other side of the piston. The sharp edge cannot take the high exhaust temperature. After 2 rebuilds for melted pistons, my next motor is getting Diamond Racing blower pistons. Also, regarding heat removal, Sterling Engines here in Detroit runs 1100 to 1400 horsepower offshore motors at a recommended 100 to 125 degrees water temp to keep the exhaust valves from burning. Anything that helps cool the valve makes sense to me, particularly a wide exhaust valve seat and thick margin on the valve o.d.
DetroitJim

[superdave013]

My 572" turbo deal is getting a set of Dart 360 heads. I already had them and they worked great on my blown engines. As far as pistions go. I have had good luck with Ross but I'm went with the JE pistions this time. Block is a Merlin, Crank is a Valasco, Rods are Carrillos with the pressure fed wrist pins. I'm making the intake plenum myself and plan on putting a wastegate on it. I'm using the superchiller intercooler and intake manifold that I robbed from the blown engine. Compression worked out to 8.1 to 1. Turbos are Rayjays that I alread had. I need some headers still and need to buy or make the carb plenums. Would love to go injected but am / have run low on money.
Your planning on running alot of boost. What kind of fuel are you planning to use?

[Terrible Buddhist]

I have a set of Ray Jays as well, I may have a plenum for sale if I go the route of FI. Are you going 1 carb or 2? I am going to run 87 Octane. Just kidding. I would most likely run AV gas or an av gas mix most of the time, and if I wanted to go play go with cam 2. I figure the FI will give me the ability to run a little less octane when I am not getting after it.
You are going to run a wastegate on the intake manifold? They made a wastegate that bolts right to the turbo with holes drilled through out the houseing...it is much cleaner than most of the setups I have seen. That is what my rayjays have.
What are you planning to run for boost? What sort of cam profile are you looking at? Tell me a little about those heads.

[superdave013]

My Rayjays have the same type of gates. Just some holes drilled in the houseings. But it made 12psi with my 461". I would think it would make even more with the bigger 572". I only want 7psi or so. I don't think your intake plenum will work for me. I an using an intercooler that used to be under an 8-71 supercharger. The thing is huge and works very good. So I am going to make my own intake plenum. The wastegate will bolt directly to this plenum. It should give me very good control of the boost. I am planning on using some Drake headers and making some adapters to bolt the turbos in place of the tail pipes.
George @ Clay Smith Cams made the cam, I'll let you know the profile when I get home and look it up. I'm going with two carbs. I have one 850 that was done up by Jones for turbo use. Hopefully I can just get another one and have the one that I already have modified. If not, then I will look into the fuelinjection. Heads are some Dart 360's with the biggest valves you can get in them. I can't remember all this stuff but it's on the build sheet from my blown engine. I went with Manley inconel exhast @ server duty intake. The springs sure look whimpy compared to the ones that I used with the big roller cam from my drag racing days.

[schiada96]

Help I'd like to do a wastegate setup for my boat. I'm tring to figure out how to dump the hot exhaust. I believe we are all talking about a draw thru applications here. So will a blow off valve for the intake "gas" side of the turbine work or is there too much chance of a fire? Aren't the blow off valves supposed to work for compressor overspeed protection? I'm need ideas.
Thanks
Jeff

[Terrible Buddhist]

There are various types of wastegates out there, I am a bit suspect of using an intake side wg with a draw through application. The obvious problem being you would be releasing both fuel and air as opposed to just air. One way is to use a wate gate that would by pass the turbo before the exhaust gets to the turbo...it would just run from the header and dump as much or as little into the exhaust pipe as you want. The way the ray jays are set up is there are holes drilled into the exhaust side of the housing, you adjust how much or how little you want to let out...this is a very nice clean set up. My guess (although I don't KNOW) is you could have one fitted for what ever turbo you are running. The final method is the budget method...drill a hole through the bottom of exhaust side of the turbo between the turbine and the exhaust pipe and then through the bottom of the flange that attaches the turbo to the header. Attach the two holes with a threaded pipe. You can then plug that hole with different size holes that will let varying amounts of exhaust by-pass the turbo.

[Terrible Buddhist]

superdave, I could be wrong, but the same size turbo should make less boost on the bigger engine, same principle as a blower...more cubic inches to stuff = less boost. I am really curious to see how that intake side blowoff valve works if you don't go FI. I really like the super chiller adapter, that sounds like a really nice setup...my thought would be to run a plenum in between the 2 turbo's...make a plate for the top of the superchiller with 2 inlets for the turbo's...that could look real nice!

[superdave013]

Terrible Buddhist, Well I have learned more and you are correct. The waste gate goes between the exhaust and the turbo. Your thoughts about the superchiller are just about what I have been thinking. I am putting the plenum directly ontop of the intercooler and ducting the turbos to it. My turbos will be on each side on the engine by the middle of the valve covers, not in the back like the were with the log exhaust.
I thought the same thing as you about boost but what I am understanding now it's that there is more exhast flow with the larger " deal and with the same size exhaust housings on the turbos the will spin faster due to the incressed velocity in the exhaust housings. So if i ever get it done I'll let you know what way it worked out.

[058]

Superdave, You may have to get bigger exhaust housings for the bigger motor. The addional cubic inches may cause excessive exhaust back pressure and overspeeding of the compressor. Do you know what the A/R ratio is on the housings you have now?

[skijake]

One quick tip"
If you are going to buy pistons that are not a shelf item, and you have to special order them, buy 10.
That way if you lean out and burn a piston you do not have to wait a whole summer to get another one.