Alrighty, im sortof at a cross road, and need some opinions on which way to go

Im am going to build a turbo highcomp motor.
I have disasembled my s4 n/a and as of know everything looks usable except the front and rear plate. They both have chunks of iron missing between the inner coolent oring and coolent passages.

Should i just buy s4 turbo front/rear and intermediate plates and build my high comp turbo motor from s4 parts?

or should i buy replacemtn s4 n/a parts, rebuild the n/a motor and sell it to someone, and buy S5 high comp rotors and build my motor using a s5 turbo block?

and one other sortof related question

Could i get a 13B-RE and rebuild it using S5 rotors and counter weights? Im under the impression that all 13B rotors are interchangeable alsong as you bring the counterweights with them, but Id rather ask than assume

-Jacob

 

actualy, scratch the which motor to build question. But i still want to know the anser the the 13B-RE with s5 rotors

 

Mind I ask why you want to build a high compression turbo engine?

 

I think by high Compression he is talking about 3rd gen rotors maybe 9 to 1's

 

You using a .96 1Fast?

 

0.84 divided

 

nope, 9.7:1

and to be different. I want to experement with propane injection to keep detonation at bay with the same motor

 

WOW .84 divided and still running 11's?? I'm taking my car to Don Marvel tommorow morning for a rebuild and we were going to go with a 62-1 .84 divided but I had thoughts of going with a .96. I was unsure what kind of HP the .84 was capable of. I'll be running a Haltech and big fmic and 1600 secondaries. What boost are you running?

 

Are those special order high compression rotors?

 

im under the impression that series 5 n/a rotors are 9.7:1

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

 

S5 NA are 9.1:1 aren't they?

 

That was running approx 13-14psi. Everyone claims this small of a housing will choke my engine but I haven't found its limits yet. Im going to be tuning for 20psi hoping for a low 11's if not high 10's. At 20psi I will be running the turbo right at its effiency limit. We'll see!

 

Kouki NA rotors are the highest (and lightest) production rotors Mazda made.&nbsp They are 9.7:1.


-Ted

 

I noticed that they are the lightest. Are they as structualy (cant spell) strong as other rotors? If i try to run them with boost are they going to collapse?

 

Yes, you got that right.&nbsp Some of the big power drag rotary shops in Japan try to keep a steady supply of Zenki turbo rotors, since these are the heaviest (implies strongest) rotors made for turbo use.&nbsp Mild detonation has a tendency to "dent" the leading rotor face on the later (Kouki FC, Cosmo, and FD) rotors; the earlier Zenki turbo rotors are most resistance to this type of damage from detonation.


-Yrf

 

I have a good set of 9.4 rotors, should i build with thoes instead of the 9.7's

Do you think a 9.7:1 turbo motor would last? or would they end up denting.

-Jacob

 

I think it would depend on how much boost you want to run and what kind of gas you plan to run. I'm more chevy V8 knowledgable and have built a few motors with superchargers and we use 8 to 1 dish pistons in those. High compression + high boost = preburn of your gas unless your running a high octain (ie 101+) race fuel.

The higher compression I feel would give you more low end power before the boost comes on but you'll probably get detonation once the boost hits hard. I'd go with 9 to 1's and keep the boost at a modest 14 psi, or if you go 9.7 to 1 maybe keep the boost down to 10-11. You should be able to run pump gas with that and 9 to 1 is higher than factory FC turbo compression. I think FD's are factory 9 to 1 though.

 

I was planning on running 93 octane (R+M/2) and was going to run some home made propane injection system to keep intake charge cooler and deter detonation

as for how much boost, im not dead set on a number, but i would like to run more than 1bar.

FD's are 9:1 i belive

I guess the big question is, hypotheticly If i can sucessfuly deter detonation, never ping hard keep everything rich and happy etc and i build the motor using the 9.7:1's, would the rotors colapse under the pressure?

 

No, the rotors won't collapse under the pressure. With the higher compression, you reduce the tolerable limits and increase the potential for auto-ignition (not detonation; this is a misnomer). It'll make decent power and lower boost pressures; there's not much reason to run gobs and gobs of boost anyways with the proper setup depending on your power goals.

B

 

Alright, its settled then, i will go with the 9.7's
Illl just rebuild my s4 n/a block and sell it, and use the $ towards s5 rotors and everything else im gona need

-Jacob