does anybody have any information regarding twin turbo rx8's or if the rx7 turbos might be able to be made to fit on an 8?

why make it more complicated than it has to be?

twin turbo = useless for us.

the 8 has side ports and the 7 has peripheral ports - a lot of modification has to be done for them to fit

^That makes zero difference, turbos are universal fitment. I assume he's talking about the turbos and not the manifold. No way the FD manifold fits, but sure, the stock twins could fit, with a custom manifold, downpipe, cold side plumbing, etc.

If you're doing twins, don't waste for the FD stock twins, they use an overly complicated twin sequential vacuum setup. Not to mention you could make around 400-rwhp with a GT2871R with a .86 A/R and it will give you pretty damn nice responce and hit full boost before 4k. There isn't an need for a twin turbo setup, unless you just want to show off.

why is there no need for twins?

why is there no need for twins? Because you can get more power, less complications, spend less money with a single turbo setup. But feel free to be the first to try this and let us know how it goes.

but the benefit of a sequential system isn't the peak power, it is the low-mid range power gained.

twin = 2......2 is better than 1...."wow this thing is twin turbo!!!"

even if you got them to fit, what ecu are you going to use to make them actuators work and supply enough fuel???????????

it doesn't have to be too complicated on a custom setup.
It is somewhat pointless in my opinion, but if he wants to turn his 8 into a low end torque freak...

Install the turbos inline. Smaller first, then the bigger downstream.
Internal waistgate for the first, as there is no high boost requirements for it and to reduce complexity and you can do the external for the second.

Set the first smaller to open it's waistgate at let's say 7PSI. After that it will dump all the exhaust into the secondary turbo.
Then tune the second turbo to boost as if you were to tune any other setup.

This actually would be very easy to accomplish.
This case you will always spin both turbos, except the first one will be coming on faster. and let go after everything is spooling well enough.

It shouldn't be too complicated.

twin = 2......2 is better than 1...."wow this thing is twin turbo!!!"

even if you got them to fit, what ecu are you going to use to make them actuators work and supply enough fuel???????????
why wouldn't you just do like the rest of the modified world does and use an aftermarket ECU like a Haltech, Autronic, Motec, AEM, HKS F-CON V Pro, etc custom tuned by a proper tuner on the dyno.

rotorocks: compound turbocharging is one way (though not one that I know of any OEMs doing on spark engines), but AFAIK you should have the smaller turbo 'downstream' of the bigger turbo so initially it 'sucks through' the bigger turbo. Otherwise the smaller turbo is a restriction to the big'un once it comes on song.

why wouldn't you just do like the rest of the modified world does and use an aftermarket ECU like a Haltech, Autronic, Motec, AEM, HKS F-CON V Pro, etc custom tuned by a proper tuner on the dyno.

What an engine manegement system has to do with controlling the acuators for your turbo systems? This definetly makes everything way complicated. Let the PCM do what it supposed to do, and use boost controllers and vac actuators do the job of opening and closing valves.


rotorocks: compound turbocharging is one way (though not one that I know of any OEMs doing on spark engines), but AFAIK you should have the smaller turbo 'downstream' of the bigger turbo so initially it 'sucks through' the bigger turbo. Otherwise the smaller turbo is a restriction to the big'un once it comes on song.

Is this what it's called? compound? Sounds good to me :)
Since I have never heard of it being actually implemented anywhere myself, I just thought it might be a good way to do the twin implementation without going through trouble of managing all the vacuum and...
If you use a big enough waistgate for the primary turbo, it should be able to flow well enough not to restrict the exhaust too much.
OK maybe a large enough external waistgate would be a better choice for the first turbo too.

Again, thi all is just a theory. I don't even see the need of attempting something like this except for a show off. A single turbo does it's job well enough.

either compound or staged. It is more common in diesels.

Trouble with a compund setup is if you intercool between stages to bring air temp back down then you get a very long intake tract.

Here is a pic (from an article about using compound VNT with electric assist - not important to this discussion)
http://us1.webpublications.com.au/static/images/articles/i1089/108916_2mg.jpg

see exhaust blows through the small turbo into the big, along with the single wastegate off the small turbo into the bigger one.

As for singles doing their job well enough - well, some of us want to have our cake and eat it too :p: , thus compound, sequential and variable geometry turbos are the go :) A 'big single' in some circles is not a big single in others. (I'm thinking supra-world where it is getting more common for 'big singles' (non-sprayed) to push out 1000+rwhp, and the stock twin sequential system capable of 500rwhp+)

As for singles doing their job well enough - well, some of us want to have our cake and eat it too :p: , thus compound, sequential and variable geometry turbos are the go :) A 'big single' in some circles is not a big single in others. (I'm thinking supra-world where it is getting more common for 'big singles' (non-sprayed) to push out 1000+rwhp, and the stock twin sequential system capable of 500rwhp+)

Fortunately (Or perhaps unfortunately), we don't need twins because no one is going over 320 whp on the renesis. A properly sized turbo for this application is going to come on quickly.

[QUOTE=rotorocks;2014802]
Is this what it's called? compound? Sounds good to me :)
Since I have never heard of it being actually implemented anywhere myself

This setup is actually used on the new BMW 335i. Just FYI.

would be nice to see

Fortunately (Or perhaps unfortunately), we don't need twins because no one is going over 320 whp on the renesis. A properly sized turbo for this application is going to come on quickly.

I think the max for the fd's twins is about 350 whp, after that its bigger twins or a big single. So a reny gettin 320 on a relatively normal/small single is quite an accomplishment compared to the old motors

You want low and midrange gains? Supercharge. You want optimal power? Single turbo.