In the rotating assembly I am looking at, I can go with either a Scat or Eagle crank, and then Mahle pistons which I must decide which pistons and which size rod (rods are H-Beams, also eagle or scat i believe).
What would be the best Mahle piston to go with for my 355 turbo setup?
I want this motor to last as long as possible and my driving will be 95% street with a maybe 5 trips/year to the track at most.
Turbo is T67 (...probably will be a T70 or T76 before it's together)
I will be running stock heads casting and would like my compression ratio to be between 9 and 9.5:1.
So which MAHLE pistons/why? (Consider the alloys too, 4032 vs 2618)
Which LENGTH of rods/why?

I understand the 2618 is a stronger alloy but with less attractive heat expansion properties than the 4032 so the 4032 sounds more street friendly...but if it can't hold up to boost, then that takes the "street friendliness" right out of the equation.

 

How much boost are you looking to run? My 2618 JE pistons work well, street driven.

 

Depends on what turbo I run. Probably 15psi max.

 

Does Mahle make a dish piston designed for blower applications? You need a piston with the correct dish to get the desired CR and you need one designed for a blower application. This will typically mean a thicker piston crown and beefier top ring land. Like I said, I am not sure if Mahle makes such a piston.

Rich

 

I'm going to make some phone calls and find out. I've been searching on this site and ls1tech for CR calculations and such and the dished Mahle pistons offered won't work for me unless I go with different heads (ie. TrickFlow) with a 64cc chamber. I would think Mahle could come up with something but maybe not!

The guy at Flatlander Racing says it would have to be a custom piston to work with the small CC on our LT1 heads. I see that JE offers a -26cc dish piston flow boost application but it looks like that would only put my CR at 9.4 which seems to be on the high side. Do you have any piston recommendations?

 

JE (perhaps SRP) also offers an off the self -31cc piston.

 

I got 31CC dished SRPs for in mine, I got my combustion chambers opened up to around 58 now so I should be right around 9.0:1

 

only for a 383 applications--not 355. Right now it looks as if I must by TrickFlow heads for their 62cc chambers.
There has to be people here who have built the 355 FI with stock head castings.

 

Have you checked Diamond brand yet?

 

for a 355 with stock heads you only need 26cc dish to get down to 9.0:1 you can use thicker gaskets and open the combustion chambers up some if you have to.

 

The dish volume quoted from Flatlander Racing's site differ slightly from the volume on jepistons.com. After looking there, I CAN get a -26cc in the JE and a -24cc in an SRP which would put me closer to 9:1. I plan on getting a valve job and having something "fly cut" (my engine builder used that term???) He said that would take out enough material to up the cc in the combustion chamber and help lower compression.
Even if I make it to 9:1 with SRP pistons, how much boost can I "safely" run?

 

9:1 you can easly run 15 lbs thats what I plan to run on my 383 when I get a D1, Ill be maxing out my P600B right now that will probably only make around 10.

 

Do you think I'll need racing fuel to do that, or will supplying enough fuel and retarding the timing a lot take care of it? 15psi is right where i'd like to be

 

thats safe on 93 pump gas, Im building my new set up that I dont need to run expensive fuel, back when I had the stock motor running 9 lbs I had to run some 110 in there to keep it from detanation, Im not doing that again with the cost of fuel.

 

I like the words you're giving me and I am sure you wouldn't be saying this stuff if it weren't true, but how does anybody know what IS and was IS NOT safe to run when it comes to Compression Ratio vs. Boost vs. Octane? Are there general guidelines published somewhere or are you talking from experience?
The only literature I have on this displays a generic graph and shows that in order to run 15psi on 9:1 CR, I would need about 110 octane. It is from Corky Bell's "Maximum Boost"; I do wish he had been more descriptive on where the information derived from in the generation of that graph. Whether or not there was an intercooler, intercooler efficiency, compressor efficiency could all be variables in that calculation. Again, I am not disagreeing with your statements, but being new at this, I would be more comforted if I knew supporting facts on the subject to go along with it.
....I wish this project counted as a technical elective in my aerospace engineering curriculum. My report would certainly contain a statement along these lines ..."turbochargers were originally designed for use on aircraft to overcome the low air density at high altitudes. My LT1 seems to have A.D.D. (altitude density deficiency) even at sea-level. Therefore, it was imperative to turbocharge this motor in order to satisfy the beast."