Reddy

Alright, this is the way I would do it. I would have a custom manifold with 8 runners. 4 would be going into the one turbo. The other 4 would be going into the other turbo. An actuator would block the exhaust flow from the 2nd one. At a certain psi and rpm I would have the actuator open up and allow both turbos to spin at the same time. I think its a bad idea to have a turbo on the downpipe of another.

Honda16hb

I hadn't thought about that idea. Why are you so against turbo on dp action? I don't think you ever told me.

dewme5

you can make more power then your engine can handle, using the normal single turbo. Why complicate things, make things more expensive, and get more headaches? Just to say you did it?

VATN technology was being used to do this simpler, but still is a worthless pain in the *** unless you want to be the guy with more money then brains.

Maybe you can run some NOS on it too. Toss in a side of propane injection, and maybe an air to water intercooler while you are at it.

Reddy

I'm so against putting a turbo on a downpipe becuase that can't be good for performance. You have to be losing exhaust velocity by running it through the turbine wheel than to a turbo. I mean think about it.

Honda16hb

ok, I didn't think about the lost velocity before, but witht the bypass I gain that velocity back once the 14b is cut out. With your 8 runner manifold design the exhaust flow is split between 2 sources, so the 14b won't have such great response.

just to say I did it is exactly why I will complicate things, you only live once, might as well enjoy it.

Jakal

could u not just run in in sort of a twin layout where u have the smaller turbo off 2 exhast ports and the larger off the other two? i mean the little one would spool a hell of a lot faster the the big one on only two that way the larger one kicks in when the smaller one is already making full boost...

Jakal

or u could run them both off of all four with a y pipe off of the stock mani.. the exhasut will take the path of less resistance which is obvious so will it spin the wheel thats allready spinning to capacity or try and spin the slower, larger wheel? would that not still be sequential if one turbo spools after the other?

Honda16hb

2 cylinders will never spool a t4, at least not in the rpm range I'm looking at. your second idea will just over spool the 14b, unless I put in a wastegate then all the exhaust will just get thrown away. I'm glad that you shared your ideas, I just didn't think they were very well thought up, keep reading and you will learn more.


that 8 runners idea sounded good to me again today when I remembered that I can put a valve in to shut off exhaust flow in front of the 14b, I'll think about that one more. Does anyone have specs on the size of the supra and rx-7 bypass valves? I didn't find much in my google searches, mostly just non-sequential conversions, what haters. If anyone sees some sequential setups on ebay for cheap post a link here please. and by cheap I mean $50 or so.

scarecrowX

it's not only the lost velocity affecting the second turbo that's going to hurt your performance. the second turbo is also a restriction in the exhaust path of the first turbo. turbo's spool efficiently based on the pressure differential before and after the turbo. with the second turbo on the dp of the first, there will be less pressure differential between the manifold and the turbine outlet (high pressure on both sides of the turbine), increasing the lag on the first turbo as well.

keep in mind too that temperature is a very important aspect of velocity in a pipe. the temperature differential between the manifold and the dp post-turbo is pretty big. that's where you're losing a lot of your velocity.

personally, i'd look into anti-lag. but i understand why you want to do it this way, and i say more power to ya.

i like the diverter valve idea. supply exhaust to both turbos, then pinch off or restrict the smaller one when the big one catches up. my guess is that wastegate actuators would be able to effecitvly control butterfly/diverter valves.

Reddy

Very good advice, Anti-lag is ------- awesome but apparently it kills your turbos. There is an antilag program on the EMS but I'm afraid to try it and you also have to run a 5th injector for the true antilag setup