Skip ahead if you want the short version.

I've been thinking about cutting out the 2nd cat for a long while. A few months back I saw a youtube video about "remote mounted turbochargers" (in cameros, NOT our cars) which is a clever way of putting twin turbos in a naturally aspirated engine. Since the manufacturer put no room in the engine compartment for a big exhaust manifold or turbochargers, this mod involves replacing the mufflers with turbochargers and running long pipes for intake air to the turbos and from the turbos to a FMIC. Since the turbos are under the car, they're constantly cooled by air.

Ok, short version:

Would replacing the 2nd cat with another stock turbo resulting in a compound turbocharger system result in faster boost? Coumpound turbocharger setups refer to a large and small turbo run in series. I'm NOT talking about that because it's advantage is achieving higher boost while MAINTAINING low end boost. Since our cars cut out at 22 PSI, seems pointless. But I wonder what two equally sized turbos in this setup would do. From my research they'd be inefficient and not worth the effort. (In fact, don't even bother commenting seriously on this part of my thought process. I'm just sharing my thoughts and I admit this part was ridiculous. FOCUS on the next bit please!)

What about this? Remove the turbo from under the bonnet, run a non-S exhaust manifold, and replace the mufflers on the 2nd half of the S exhaust w/two stock turbos. Twin turbo setup resulting in faster boost, right? If everything was set up to mirror the stock setup and the only changed variable was parallel compressors producing equal-to-stock boost FASTER, a tuner would need only to adjust the ECU's expectation of spool time, no?

It would require custom piping from the air intake box to the rear of the car, custom piping from the rear of the car to the FMIC, and routing oil from the engine, to the turbos, and back.

All of this would be a HUGE headache, and I'm NOT interested in attempting it because my MINI is daddy-mobile daily driver... but I thought the idea warranted a thread and would have some interesting discussion. I've read a lot about putting a BIGGER turbo on the N14 (or N18) and nothing about running a twin turbo setup.

 

I thinking that it would result in tremendous delay in boost because of all the long runs of piping.

 

Let's pretend there's enough room between the engine block and the radiator to mount two turbos. Employee a custom exhaust manifold and twin turbos. I'm dreaming here anyway. Why hasn't anyone done this?

 

I think that our turbos spool pretty darn quick. My data logging shows that if I'm cruising along at 3000 rpm in 3 or 4 gear, then go WOT the car is at full boost by 3200 rpm.

I don't know if we would benefit from two turbos. The displacement of the engine is quite small.

 

10.5 PSI at 3200 or greater? Our turbo spools STUPID fast to stock peak PSI, but for those of us running increased boost it's woefully slower between 10.5-->20PSI

 

I using the JB+ so I normally peak between 13.5psi - 15.5psi depending (mostly on temperature), lately it's hitting about 17psi in the summer heat.

 

Whats the point?

 

Because racecar

 

This is probably the reason why no one has done it. This was on my mind so much yesterday that I dreamed about it. I've NEVER seen a turbo charged motorcycle. Why? No need I guess?

Anybody else's thoughts?

 

I stand corrected. Google turbo motorcycle and a LOT of stuff comes up. I couldn't find a factory turbocharged bike but people definitely do it.

 

Actually there were 4 OE Turbo motorcycles, all in the 80's.
Honda CX500t
Kawasaki GPZ750 Turbo, and the Holy Grail of street bikes the Z1R Turbo.
Yamaha also made one the name escapes me right now, but it was 600 or a 650 cc. I think it was a Seca Turbo.

 

Google lied to me? I'm shocked! =P

 

Borg-Warner EFR 6758 (IMO), is the ideal replacement turbo.

 

Yes it did.. My brother in law is running 650 hp on a turbo busa.. Crazy built up motor, 6th gear power wheelies on the hiway

 

The problem I for see is that the engine we have and most 4 bangers is that they do not flow enough exhaust to be able to support a twin turbo set up. Now doing something like a twin charge system would work(turbo and super charger). I want to say it was Helix that twin chargered an R53. That would probably work. Well then again it depends how much kick back you get from the ECU.

 

Just go with 2 engines :P https://www.youtube.com/watch?v=7YL7pURth3o

 

For reference, here's a rear twin mount mustang.

https://www.youtube.com/watch?v=kTUK4Oj9_Hk

Yes, it's a lot of piping but I don't think they suffer too much from lag. That or because of the engine displacement and gearing, there's enough low end grunt to compensate for any lag.

For the MINI's engine size, I imagine its all about safely wringing as much boost as possible.

For V8s and the likes, they typically run lower boost numbers.

I had a supercharged gen 1 Lightning (95'). 351w (5.8L) running just 5lbs of boost and that thing would scream. I miss that truck.