You could use a dual inlet, single outlet intercooler =[ ]-

 

I measured and cut the bends and had someone else TIG weld it, since I have no welding skills and no welder. And yes, being off 1/8" is the difference between the rear turbo interfering with the LIM or the turbos interfering with each other. I did a lot of trimming, having my friend hold the manifold runners from underneath the car while I held the turbos, etc. My back got sore very quickly.

The manifold is very simple; I use a 2.5" J bend for the rear and a stubby straight one for the front. The downside is that the rear runner is a good bit longer than the front, but it really shouldn't affect anything, in my opinion. The rear may spin a tiny bit slower since the exhaust gas will lose more heat by being absorbed into the rear runner prior to entering the rear turbine housing, while almost all of the energy of the front outlet will be expended in the turbo. The rear has more volume in which to expend exhaust energy, and the pulses have to travel a greater distance. Again, I am not a fluid dynamicist (I'm sure someone around here is), but I doubt there will be any considerable difference, nor any more than you have with the asymmetrical design of the factory twin manifold.

This is definitely not a complete solution. I am still facing the challenge of making a viable downpipe for the front turbo, since it has to dodge the rear runner. There's going to be an odd bend or two to make that happen. I have to worry about how radiated heat from the rear turbo is going to affect the LIM. I don't have a lot of room for a heat shield of any type so I'm going to have to rely on a ceramic coating. On top of that, I have to make the wastegate actuators fit with the odd clocking, so I have to drill and tap the compressor housings to accept the actuators in their new orientation. I have a lot of work left. Suggestions are welcome.

Incidentally, does anyone know where I can find some T25/T28 outlet flanges with the machined-out wastegate pockets? Forced Performance had some but they've been out of stock for a long time, and it would probably cost me more to have them made locally.

I had that thought -- maybe, maybe not. I don't have the knowledge or tools to do that analysis. I have two equal size chambers and two equal size turbos, so I don't think so.

 

I'd say you would create more problems than you'd solve. You would end up giving the exhaust gas more area to transfer heat energy that could be used to spool the turbos. Both turbos will feed into a single intake plenum, so as long as there's not too much difference in the exhaust manifold length, the proposed setup shouldn't create any problems.

 

Here are a few pics of the manifold. That runner is pretty short... This is prior to any finishing; I still have to die-grind the inner edges of the flanges and ceramic coat the whole assembly with the housings attached.

 

I was just working on my turbos tonight and the one thing I remember not being terribly happy with in my setup is the oil drain lines. How do the single turbo kits deal with it? I used part of the OEM tubes where it bolts to the block and then welded AN fittings and -10 lines then just normal braided -10 up to the turbo. Does someone have pics of single turbo oil drains?

Kevin T. Wyum

 

BTW how are you dealing with wastegates?

 

Are you going to plumb two boost line into a single boost gauge and a single boost controller?

Or are you doing two gauges and two boost controllers?

 

are you planning on selling kits of this by any chance (after you've got some proven dyno numbers of course )? i've been looking at going for a single, but am really more interested in mid-range power than top end just curious and all. awesome idea though.

call me an idiot (when it comes to turbos i still am, so feel free to), but how is this much different than running the stock system in a non-sequential set-up??? is it just that each turbo is plumbed to a single rotor and the stock system is plumbed to both?

 

are you serious?

 

lots of questions...

On the oil drains, Kevin, I was very happy to discover that this model of Garrett has a 5/8 pipe tap directly on the bottom of the turbo, so I can screw a -10 fitting right into it, and take it down to flanges at the oil pan. The way that I've handled it in the past is to take a stock oil drain gasket, cut out a flange, and then tap it for pipe thread (-8 or -10), tape and install the fitting and then cut and belt sand the fitting down on the back of the flange flush so it seals.

On the wastegates, I'm using the internal ones, and porting them out a bit. I may well run into boost creep issues, I don't know. If I have severe boost creep, I may have to start over with an X-over manifold with an external wastegate in the middle - I hope I won't have to do that. In all, the wastegate flappers are about 1.25" in diameter, so with some porting I should be able to get good flow - we'll just have to see.

I would say probably not. I just don't have the time right now, or the quality control. I'm risking my own car, time, and money here, and I don't want to risk yours.

1) Cool factor
2) Hopefully better exhaust & compressor flow
3) Some simplicity
4) Cool factor

I've been busy working on the fuel system; as I get more done on the turbos, I'll put some more pictures up.

 

ok, so maybe not as kits... but if you got really good performance/bling factor out of this would you be willing to do a 100% complete write up for us (me) so i could put my own car at risk?

 

Sure.

 

Why wouldn't I be? He's running two turbos independently with two separate waste gates.

Is he going to control both waste gates with an average boost reading or is he controlling each waste gate individually?

 

Since the turbos feed into the same manifold, there will always be one boost pressure. If I had two banks and two throttle bodies (as in a V6 - say a 300ZX TT which IIRC has twin T/B's and two manifolds - I could be wrong), there might be a reason to use two boost gauges.

There's no reason to use multiple boost controllers. The wastegate actuators are the same, the turbos are the same, and I want the wastegates to open at the same time. I probably won't use a boost controller right off - the spring tension on the actuator is set for about 10 psi, which should be good for a baseline to get everything running correctly.

If I use the AEM PEMS, I'll use one of the custom output maps and probably use the stock W/G control solenoid, or a custom solenoid instead of spending another $300-$500 on a boost controller.

 

Here is a pic Kevin. Flnge is made that bolts up to the front oil drain. You can either make a long one or a short one depeding on how you want to do it. Switch the runners round and you can get them equal length, I think you may wind up putting too much heat on the front turbine wheel. They've been known to melt at times.

 

The heat issue does concern me.

Do you think I should put the EGT and O2 sensor in the rear runner, both in the collector after the turbines, or the EGT in the runner and the O2 sensor in the collector?

 

Are you sure they only flow 23lbs/min each? 46lbs/min is only enough flow for around 360rwhp. You have a compressor map for it?

BTW - Where in Al are you? Have we met? I'm in B'ham

 

23 lbs/min is for a T3-60, not the TB25 - that was someone asking about another turbo. I haven't been able to find a compressor map for the TB25. It looks like it's somewhere around the same flow as the T3-60, however, but I'm sure the wheel has been redesigned since then, so it may flow better, around 23-25 lbs/min hopefully. Our numbers do agree; I estimate 350 wheel at 1 bar.

 

Huntsville. Have we met?

 

Thanks for the pic Zero, I'm kind of surprised they used a plain rubber line, I take it you meant the lines sometimes melt?

Kevin T. Wyum

 

no guys, he has a point...i think he's onto something, you should also consider dual ECU's so you can run seperate maps for the injectors front and rear, I mean, if you truely want a twin setup, you'll have to treat each rotor like a seperate engine

might want to look into dual ignitors and dedicated coils too

 

I think your map suggests 370 eng hp at 14.5 psi and 8k rpm. for 350 rwhp at more realistic 7500, I think mabe 16 psi, for 20 lb/min per turbo.

A T25 compressor is vey efficient, and could be more efficient than the T28 at this power level, with quicker response.

For integral wg turbos, the T25 turbine outlet is much better designed than the T3, and allows a bulged, split dp entry to reduce exh gas conflicts that rob top end power. Check the top of this page, for MRT design.

http://www.autospeed.com.au/cms/A_08...popularArticle

 

Then you should probably consider using Inconel instead of stainless tubing for the production exhaust manifolds.

 

That outlet adapter with the flow plate welded in is pretty slick. I wonder if they would sell me those flanges without the catalytic converter attached...

 

I think I found what I was looking for:
http://www.atpturbo.com/Merchant2/me...de=ATP-FLS-015