198713bt

iTrader: (2)

I am building my engine right now with s5 turbo rotors, and I was curious if the s4 turbo ecu would be dangerous to run. I don't want to have issues caused by the higher compression and i dont know how much different the timing is with the s5 ecu to compensate for the compression. The plan is to eventually upgrade to 720's and run rtek 2.1, but I want to get it running and broke in before I start spending money on performance upgrades. What do you guys think?

198713bt

iTrader: (2)

Anybody have input on this????

The_Eff

I had S5 NA rotors in my S4 Turbo engine for last summer, 8K miles on it and had no problems.
As for the ecu, timing is the same, but I think the s5 has a better knock control unit.

lastphaseofthis

iTrader: (8)

s5 N/a 9.7 to 1 compression ratio

s4 Turbo 8.5 to 1... CR.

and you're telling people the timing is the same.. happy blown motor...


for the record.. i run s5 N/a rotors in an s4 Turbo engine. on 87 octane! and with stock timing, i didn't get any knock as long as i had 93 octane gas... with 87, i had to retard the timing in all boost areas over 2 psi...before, it knocked real bad..

OP

s5 turbo rotors are 9.0 to 1 CR... you should be fine with a stock ecu and stock boost levels, but you way want use 93 octane for safey's sake.

198713bt

iTrader: (2)

If you guys ran NA rotors I'm just going to assume that my 9.0:1 rotors should be just fine for a little while. Thanks!

flaco

iTrader: (7)

is not fine for a little while. as long as you have the right afrs and the right timing you will be fine. just dont go all out on the boost thats all

lastphaseofthis

iTrader: (8)

Port the waste gate if you have ANY exhaust mods.

The_Eff

Timing marks are at 5Degrees, S4 and S5... Or maybe i'm just stupid and the FSM too?

And thank you, but my motor isnt blown.

198713bt

iTrader: (2)

Timing marks don't mean the ECU's run the same timing.......