This is all theoretical, but if my Chinese manifold cracks, I'm going to build my own from scratch. I was in the junkyard and noticed these absolutely tiny turbos they have on late 80s and mid-90s turbos. I was thinking about building a twin turbo manifold with these because they're cheap and spool up easy and that would probably help a lot with lag.

I attached a couple of pictures. I had no idea they made turbos that small. It's called a 13c turbo and it's made by Mitsubishi.





Crazy idea?

Hahaha, those are ridiculously small. Something that not even a motorcycle would have! A compound turbo setup wouldn't even be that great with such a small one like that.

Go for the gusto. Twin TD05-18Gs.

I've considered twin, twin scroll turbo's just because. But then I realized I don't have limitless funds, LOL! That being said though, by today's standards, there would be little to gain. It would be really responsive, but it wouldn't make much power either. Those are REALLY small turbo's. You could get the same response, and power, with a simple bolt on single turbo like a GT2560.

It wouldn't be more responsive than a proper twin scroll setup, but it would be much more of a PITA to build. If you want ultimate response, look at what small twinscrolls, like 328i-s, V40 T4s, or Renault Megane RS-s are doing nowadays. They have flat torque from 1800 up to whatever with twinscroll TD04Ls, which are TINY hotsides compared to what we are used to seeing, and they can get 300+ hp out of those with various compressor upgrades. My next plan involves one of those stock cast twinscroll manifolds with an adapter plate.

Unless you are looking for the WOW/uniqueness factor. In which case, just ignore anything I said.

Sorry, I missed this. The proper name for these is a TDO4H-13C and they're $40 at a PickNPull. The only turbos I've ever seen there except an occasional Mercedes' one.

I honestly laughed when I first saw one. It looks like it belongs on a lawnmower. Kind of like this bad boy.

How big is that guy's yard? Crap! Small turbo? Try the one on my old truck.

dhen wrote:Sorry, I missed this. The proper name for these is a TDO4H-13C and they're $40 at a PickNPull. The only turbos I've ever seen there except an occasional Mercedes' one.

I honestly laughed when I first saw one. It looks like it belongs on a lawnmower. Kind of like this bad boy.

TD04H is not that small. Smaller than a GT25xxxsomethingorother, but not small enough to use two as twins. OEMs put ONE, tiny bit smaller TD04L on stock 240-250hp 2.0 liter engines. TD04L-13Cs are the twins on the 3000GT's. I don't know what those as twins are going to do on a 1.8l, but I'm sure it won't be fun. If you want twins, you'll have to go even smaller.

But still, from a pure technical point of view, the advantage just isn't there. Two complete rotating assemblies you have to keep spinning, with half of the exhaust gas that you're used to having. Dual downpipe, dual chargepipe, dual inlet pipes, dual oil feeds, dual oil drains. Not to mention very small turbos are not very efficient, and definitely won't do big pressure ratios.

It's purely a freak factor thing. You could do a set of twins that would do something on a dyno, but they wouldn't be very livable on the street. A properly sized single would always be better performancewise.