So is around 400hp all the renisis ever going to handle or is it just a matter of time before more and more 400+ renisis 8's start running around? And if 400hp is all that it can hadle, then why is that? the motor just can't handle the stress? even with proper tuning, porting, fuel, cooling, and seals?

 

Well right now I am not aware of a single turbo on the market for the rx-8 that puts it at 400 hp. Maybe give it some time. Mazdasports turbo should be realeased very soon and I hear that had some big numbers. I am sure the motor can handle the stress, what makes you think it won't?

 

I'm sure it can handle 400, and actually the currant kit i have was done by mazsport, and i plan to have them do a gt35r next, but on most threads it seems as if everyone is saying 400+rwhp is not realistic. I guess there's a couple of 400+ renisis 8's in puerto rico but i haven't really read too much into those yet. Basically my question is will the renisis ever come near to such power output like the 2jz, rb26, or even the 13b?

 

the engine is fine. it's the compression ratio that's limiting the hp potential on pump gas.

grab a 4-port motor with a big turbo running c16 and 500+ should come without too much trouble.

 

the 2jz and the rb26 are good motors, but they have their cars. Neither of which is lightweight.

Leave the highrevving engines the rx series

 

Like GuitarJunkie said, it's the compression ratio that is holding the engine back. In all honesty, I think it is very impressive that there are Renesis engines pushing more than 300 whp on 8-10 psi tunes. If you reduced the CR, and upped the air going into the engine, a lot more power could be made.

 

Haha When i saw RB26, i had to think for a second that its not R26B.. =D
________
Hey_Hey cam

 

Hmph, now that would be insane. By the way guys, I've been registered on this forums, but I found where I left my id and password written down. Someone deleted my e-mail confirmation.

 

Why do I keep seeing this junk about the "compression ratio" being a limiting factor - especially from seemingly knowledgable people?

The combustion process doesn't care how the charge got so dense - whether it is from static or dynamic compression inside or outside the combustion chamber.
More static compression just means less boost is needed to achieve the same combustion pressure.

 

^^ it just means the idiot tuners blow up engines earlier that on a lower compression motor

 

so what you mean is that a 13b with a t4 would need more boost psi to run 400hp than a a renisis using a t4? sorry to sound stupid, but like i have said before this is my first turbo car, not to mention rotary. so if it's not CR? then what's this limiting factor/factors of the renisis?

 

Well first of all, both engines are 13B's. Except the Renesis is side port with bigger exhaust and intake ports and higher compression ratio!

Let's do this>

Take a 1993 FD engine and strip off the stock turbo's and bolt on a T4.

Now take a Renesis and bolt on a T4 and run both engines at the same psi at about 8psi and see what the peak hp is?

 

I don't know too much about engines except that when you want to run high boost, you typically have to lower the compression ratio. This is typically done by putting a spacer between the block and the head - but we can't do that. I'd like to refer you guys to a post on this issue by rotarygod here.. https://www.rx8club.com/series-i-tech-garage-22/advanced-renesis-tech-99617/

He said, "Years ago Mazda found that there was no appreciable difference in power on a naturally aspirated rotary with compression ratios from 9.0:1 up to 11.0:1. Virtually no power difference. So why then would they do it? Emissions! Yes, emissions...... This results in improved combustion stability at low engine speeds and loads. I know many would like lower compression ratios for boosted applications but emissions comes first to Mazda. Boost is for you to work out!"

So what I got out of this post is two things.. assuming both are correct.

1) Reducing or increasing the compression ratio makes no difference in power.
2) Lower compression ratios are better for boost.

Confirms what I've heard elsewhere before and what is being said here.

My thoughts.. figure out a way to decrease the compression ratio for the Renesis and you'll be set to go high boost. Is this doable or has it already been done?

 

JIC has a 445 HP RX-8 (claiming they will go above 500 HP with it).

Its using a HKS T04Z turbo. http://www.rx7store.net/product_p/hks%20t04z%20kit.htm

The English web page is http://www.jic-magic.com/ Japanese web page is http://www.jic-magic.co.jp/

At their website, they do have contact info. and phone number, so perhabs somebody can get more info. out of them. They seem to only give limited info. about their cars and specs at their webpage, concentrating more on selling parts, but there is a gallery with a few pics and some event info.

Another car KDIV RX-8 at www.ks-auto.com is claimed to be at 445 HP too.

http://www.ks-auto.com/turning/democar/kd4/index.html

I'm not clear on the type of turbo they are using. Some places said greedy and some sources say HKS T04S ( like http://www.turbochargers.com/Turbos/...rades/T04S.htm ). At 445 HP, I'm thinking its the T04S.

 

JIC is using a 13b Rotary, not the Renesis. I think the original post was asking how much is possible for an RX-8, which assumes he's talking about the stock motor.

Once you bring in motor swaps... everything flies out the window and your just comparing apples and oranges at that point.

-hS

 

yes i meant how much can the renisis put out

 

Well somebody like RotaryGod would be better at answering that question.

I think the issue is with the ECU and tuning. You can put a big turbo on the Renesis and get high boost, but if you don't want to blow your engine up than you are going to have to tune it properly and make sure other parts like your exhaust, fuel system, etc... can handle it.

So far, it seems many tuners have been very conservative, because they want to add power but they also want to make sure the engine lasts a long time. Therefore, I think they have kept power gains close or under 300 HP. Also the RX-8 is still pretty new. Many RX-8s are still under warranty, so many don't want to risk going turbo or supercharger until the warranty is up.

I think you will eventually see more 400 HP RX-8s in the future. As more warranties expire, I would expect more people to want more power. There are a couple of turbo kits that appear close to 400 HP and in the high 300s. I think its just a matter of time, before they come out with a 400+ HP turbo kit. Then the issue will just be about money, as I would expect such a kit to be expensive.

Lastly, people wanting 500+ HP are going to be few in number. The RX-8 is only around 3,000 pounds. It does not need as much HP to get it to move fast for the STREET. Heavier cars in the 4,000+ pounds range need more HP to move them. You start talking a RX-8 with 500+ HP and all the MODs that will take you to get there, than you are not looking at a daily driver anymore. You are looking at close to a race or drag car, that is for the track. I think a lot of people will be happy with 300 HP to 350 HP, as oppose to 500+ HP that is super expensive and require lots of MODs.

 

I do agree with the point of less wieght needs less hp to push it, I'm just wondering about the 500hp thing, mainly because alot of the people i know have pretty high hp cars in comparison to my 8. So i'm just in the never ending bettle for high hp, i hope i didn't make anyone think that I want to run 500hp. like i said before it was just wonder whether the renisis is capable of it.

 

I had run a 65 hp shot of nitrous on my 8 and let me tell ya, when that nitrous boost kicks in, it feels like the car is gonna take off and fly. It is really fast. and that is like around 250 - 260 to the wheels? With 300 - 350 at the wheel, the car must be a neck snapper. 500 - it will not be drivable. at a part throttle maybe but never at it's fullest.
It will simply be at least 100 HP more than anyone will ever need. 99% of the time you will not be able to use it.

 

at this time i'm already near the 300rwhp mark, and like i mentioned before i realize that 500 is alot, i never stated that i wasnted that much i just wonder how much has to be done to a renisis to put out that power

 

thats a good point, they say its tough to transfer 300hp to the street, imagine over 400hp. but it would be a highway monster.

 

[QUOTE=sosonic]You start talking a RX-8 with 500+ HP and all the MODs that will take you to get there, than you are not looking at a daily driver anymore \./QUOTE]

Not really, look at rgonza. He has a...what is it.. 650 whp or so 3 rotor beast with turbo and it is his daily driver, or so he says. I forgot what his numbers on the drag strip were though, or I never read them. I think it was right at 11 second quarter mile or so...

 

ehhh...it's not like it's not streetable, I mean it spins a bit in first and right at second, but it really behaves no differantly if i'm not trying to haul and if i can push 400 with the new turbo then i'm pretty sure i'll be done with trying to make it co anyfaster...well atleast in a straight line.

 

god i can't type worth a crap...lol

 

[QUOTE=t-run/8]rgonzas car will loose traction at WOT in 6th gear. I think he even mentioned that in his tread.