I am in the process of getting parts to do a compound setup and had some ideas I wanted feed back on.

I already have a non waste gated 12 housing for my HX 35/40 and would prefer to use it. I am considering building a short extension flange to go between the exhaust manifold and the turbo where I could mount an external waste gate. The WG flange is small enough the extension would be less than 2 inches and the WG could then feed right back into the exhaust stream on it's way to the big turbo (S475).

What about a waste gate for the large turbo to control total boost, needed? advantahes/disadvantages? I really like the idea of in cab boost adjustability.

I have heard of the ricers breaking turbos if they don't use a blow off valve, is this something that is only an issue on gas motors?

Maybe I am trying to over engineer somthing that is really simple, let me know what you think.

 

Good plan but it will be better to exhaust the wasgate to the down pipe and run a controller in the cab

 

Which waste gate? It seems to me the first WG contolling the top turbo should dump back into the exhaust stream so that the big turbo gets all the exhaust, not just what comes from the top turbo. Dumping to the down pipe will be a waste of exhaust heat and pressure that could be used to help get the bottom turbo spooling, right?

 

Right, also it's highly doubtful you will need a wastegate on 475 unless you are planning on tons of nitrous. The blow off valve for gassers is something to do with the throttle plate?? Not too sure on it but basically, from what I've read, when you let off the throttle on a gasser, there is a plate that closes, stopping air from going in the engine. If this air is not blown off it has nowhere to go. Not needed on a diesel except with some mega HP mega sized turbo setups.

 

That makes sense on the blow off valve. The diesel engine with no throttle plate just let's the excess pressure vent out through the cylinders without the slam of air boost into the closed throttle plate causing a pressure wave of reversion directed back to the compressor.

That is good on not needing a WG for the large turbo as the high flowing WGs run 4-5 hundred

 

I meant an external between the manifold and top turbo i would think with a 12cm housing you would over speed it and bam blown turbo and those parts goin in to the bottom one

 

Yes, that is the plan, external wastegate in between the manifold and the turbo dumping back into the exhaust flow to the large turbo, besides with the back pressure created by the 12 tubine housing the restriction would choke off the large turbo from the exhaust flow.

 

I agree guess i needed to read your first post

 

You've got the right idea. You want the WG to dump into the hotpipe to help spoll the primary. If you're useing you Dodgezilla you'll have a nice setup. You could just use your 14 housing. It'll save you some money. If you use and external WG make sure it's a piston style and not diaphram (Tial).

 

Thanks, yes the Dodgezilla will be the top turbo. Would it be advantagious to use a 12 turbine housing? or is that something to leave and change as needed while tuning the set up?

The 12 turbine housing would spool to boost quicker, opening the WG sooner, to help the 475 spool sooner, right?

 

The 12cm housing will help with spool, but it's so small it's also a choke point and will hender flow.

If you already have both try them and see what better suites you and your needs. I personaly prefer top end flow over instant spool up.

 

Yes but unless you're running a highly modified 14mm ve pump, they kind of run out of steam on the top end, like 3500+. Even with the 14mm piston, they don't like to rev either. I doubt a 12cm housing up top with an external gate is going to limit the top end too much.

IMHO I would go with the 12cm housing with an external piston style wastegate dumped into the hot pipe. Should give you good spool, and also plenty of flow around the small housing.

 

I opened up a WG'd 12cm and made a collector than replaces the backing plate. Drilled out the wg port to 15/16", removed the divider and ported it. Make the hot pipe 3" to keep velocity up, unless you have a true 4" outlet secondary. The internal gate is adequate for most 1st gens, I think. Plus it makes path more of a straight shot. Mine seems to spool very quick, granted I have nothing to compare it too. I only have a HT3B/27 for a primary, not sure how much more a 475 will flow than that. 60mm 8 blade compressor on the H1C. The highest boost I can get on the street is about 58 psi(stock non-IC inj.with water-2-air IC.), drive reads about 55. I don't know how much more fuel it will handle before the drive gets out of hand.





Look at how many kits use internal gates on the s300's. I think that with the opened up WG a H1C/HX35 will work quite well for the money.

Just some ideas.

 

Another fabricatin' fool!!!! I have a blue box welder in my shop too, but it's TIG, SnapOn for the MIG, I still can't figure out how I made it all those years with out a plasma cutter, it rocks!!

I am going to lay the WG pipe into the hot pipe at enough of an angle I think it will be OK, I had not considered 3" hot pipe before you mentioned it, I will probably do that, makes sense.

I can hit 42 PSI right now with the Dodgezilla. Where are you pulling drive pressure from?

 

You will want total drive pressure, so in the manifold right next to your pyro. Or you could just use the pyro port for testing.