hey guys my engine went out last night and i am going to be rebuilding it myself. i have 2 rotors from my old na that i never used to rebuild it. 1 thing is that the side seals are kinda stuck in there. whats the best way to get them out? also i want to use these rotors in my turbo motor. they are both from a s4. would i need a na counter weight or somethign to keep it balenced. i know that they are the same weight but isnt the weight in different places becuase of the different size grooves?

 

1) soak the side seals/ grooves with solvent, then use an old side seal or an exacto-knife (with the point broken off) to CAREFULLY extract the side seals/ springs
2) I'm not sure, but I think the S4 n/a & turbo counterweights are the same (somebody will let you know if I'm wrong, I hope)
3) with the n/a rotors, you'll need lower boost for the same bang, or something like that...

 

Also, the rotors are much lighter as I recall. As Wayne said, MAKE SURE YOU RUN LOWER BOOST, or else you will blow something up. The NA rotors are much higher compression.

 

well with the stock turbo im gonna be running 8-10 psi on these rotors. then when i got to a 60-1 i will be about 12-15. that should be alright right?

and im pretty sure all s4 rotors were teh same weight jsut different compression. 8.5:1 for turbo and 9.4:1 for na(which i will be useing)

http://www.mazdatrix.com/faq/rotorwgt.htm

 

the weight of something, and the rotational balance weight of something, are two different animals...Like the fan blades on a turbo jet engine, they can weigh exactly the same, but have entirely different moment-weights...and did I read correctly- you want to go 12-15 psi on N/A rotors????

 

i know that they are the same weight, and i know that they have different weights on different parts becuase of the grooves from na and t2 rotors are a big difference. that was the purpose that i made this thread. so does anyone know what i would need to do to use na rotors? i know other people have done it.

and you think thats too much? what should i be useing then with na rotors max?


and how will this be on the stock ecu? i will be useing the stock ecu untill i can afford ltx8. so like 2-3 months of stock use wit this set up. how will it be? do i need to change timing?

 

On NA rotors i would say 10 psi would be the max you could push and that's if you're lucky.

 

People seem to get real panicky about increasing the compression in Turbo engines, but as long as you do it right you'll be fine. You need to remember that both boost and compression add heat to the fuel/air mix, so effective intercooling and cold air intakes are a must. You can use the effective compression ratio (ECR, basically CR multiplied by the pressure ratio from the boost) as a guide to how must boost you can run. If an 8.5:1 CR engine can run 12psi safely, and you change the rotors to 9.5:1 (i.e. S4 Turbo rotors to S4 NA rotors), then 10psi boost will give you about the same ECR, and be just as safe. It will also make similar power, but will be torquier and more flexible, particularly off boost. There's no such thing as a "maximum" amount of boost you can run with higher compression. You just need to make the right allowances for it.

 

thanks nz for clarifying that, but do i need to do anythign special when putting it back together for it to be balenced. becuase dont the na and turbo rotors have weigth in different places? do i need to use the na counterwight or anything? do i need to worry about balencing it?

 

BUMP

 

NZ...you are a smart, smart individual.

 

i dont see any reason why not either...just give it plenty of cold air and lots of fuel....the rest should be ok....and u'll have a better motor than a stock t II...

 

Would a stock intercooler work then? What if its changed to front mount?

 

Cooler air the better, in any circumstance..
Heat is a cumulative thing.

It will 'work' with a stock TMIC, but it would obviously work much better with a FMIC, just as a normal 'low' compression turbo motor would.

 

You guys are crazy. I hit 13psi on my 6port N/a with the stock turbo without a problem. Just do as NZ said and make sure you're tuned for it.