newbie trying to choose a 13B

[Raksj04]

I was told you can make good power with the N/A rotors in a 4 port engine with a turbo. I think the s4 NA rotors are 9.4 and the S5 is 9.7. and the S4 turbo is 8.7:1 and the S5 is 9.0:1. those where off the top of my head. The RX8 rotors are 10.0:1 but they need to be machined to work in a older engine. I know the apex seals are different and I believe the corner seals will cause you issues. It is just easier to run the 9.7:1 S5 N/A rotors.

here is the ratios and weights, I was off a bit.

Rotors: The S5 rotors have a higher compression ratio and lower weight than the s4 rotors.

S4 13b 6PI: 9.4:1 compression ratio ~10lbs
S5 13b 6PI: 9.7:1 compression ratio ~9.5lbs

S4 13b Turbo: 8.5:1 compression ratio ~10lbs
S5 13b Turbo: 9.0:1 compression ratio ~9.5lbs

[RICE RACING]

13B-REW and a 300bhp shot of Nitrous Oxide is what you need

[My5ABaby]

Originally Posted by Raksj04

I was told you can make good power with the N/A rotors in a 4 port engine with a turbo. I think the s4 NA rotors are 9.4 and the S5 is 9.7. and the S4 turbo is 8.7:1 and the S5 is 9.0:1. those where off the top of my head. The RX8 rotors are 10.0:1 but they need to be machined to work in a older engine. I know the apex seals are different and I believe the corner seals will cause you issues. It is just easier to run the 9.7:1 S5 N/A rotors.

here is the ratios and weights, I was off a bit.

You can make good power with the N/A rotors in a boosted engine (which is why I'm doing it), but the chances of detonation are higher due to the higher compression. I'm fixing this with e85 but a lot of people probably aren't willing to do that. I'm only doing it this way because I'm starting with a N/A platform. If I had my druthers it's just easier to start with a TII block.

[RICE RACING]

No way ever would I use higher than 9.0:1 compression rotors as found in the S5 onwards turbo engines. Do not recommend it for any fuel types in human existence. You will always need to run non ideal fuel mixtures and spark timing and all of these factors point towards the static compression being WAY TOO HIGH.

[TitaniumTT]

Originally Posted by My5ABaby

You can make good power with the N/A rotors in a boosted engine (which is why I'm doing it), but the chances of detonation are higher due to the higher compression. I'm fixing this with e85 but a lot of people probably aren't willing to do that. I'm only doing it this way because I'm starting with a N/A platform. If I had my druthers it's just easier to start with a TII block.

There are other ways to fight off detonation rather than using E85. My big concern with E85 is that you don't always get E85. So you tune for E85, then get a tank of E70 thinking it's E85 (making up numbers here, I don't know what the actual variances are) and then what happens? I would rather go with something that can be had consistantly. Or get one of those sensors that senses the amount of ethanol and trims fuel and spark to suit it. That would be trick, but a pain in the ass to tune, although once you did get it, you would truly have a flex fuel vehicle.... funny how the OEM's did it that way

Or just drop in some turbo rotors.

I'm thinking about putting in a set of the the S4 n/a rotors into the 'vert. But this will be a low boost, stock turbo engine. A little more compression to liven it up down low... but we'll see.

Originally Posted by RICE RACING

No way ever would I use higher than 9.0:1 compression rotors as found in the S5 onwards turbo engines. Do not recommend it for any fuel types in human existence. You will always need to run non ideal fuel mixtures and spark timing and all of these factors point towards the static compression being WAY TOO HIGH.

This is a true story, but again, horses for courses as you put it. If you're running minimal boost on a stock port, stock turbo engine, it can liven it up a bit in the vac/cruise ranges.

[RICE RACING]

E85 is a total certified nightmare > read here > http://www.ausrotary.com/viewtopic.p...de809551254e98

I convert one car a week back from that bullshit to gasoline and water injection. I am not the only person either, across the country MANY people are doing the same, there are so many horror stories running this hyped up shit its unreal............. most are too ashamed to admit how many engines that they have destroyed as a result of running E85 crap!

You need to see what it does to your rotor bearings after it contaminates the sump oil, again something no one will tell you about, but is a well known fact in the "industry" For road cars E85 is a total con job, its really a race fuel and a very poor one at that given how often it fucks engines.

I was waring people from the outset of this bullshit being promoted as gods gift, and its turned out to be the BDC of fuels.