Good start to the new year.

Benny's graph looks really good, and its why I got your turbo's. He is using garret housings I'm using the hypergear housings is it possible that the housings are restrictive?

 

If you convert HP to KWs you find the KM/H vs Power in mid range is identical. He's got injectors and a custom tune maxing more top end while I had to drop off boost so it doesn't pin.

Casting wise they all .45 comp with .63 rear, The only difference is the comp housing casting that I've been buying is off T25G so the bolt flange for the cooler pips is slightly out. I've had that modified now to suit OEM flange. Port wise they are identical to standard housings and I've tested that to flow 230rwkws per turbo on a CA18det. So it shouldn't be the issue.

I think the high EGT is more likely been from those dump pipes or other restrictions related to flow.

If you really believe its the housing castings are not big enough I don't mind machine out your stock housings to suit your current CHRAs at no cost.

 

the weird thing is that benny's car had n power crappy dumps then too

 

haha I was thinking the same thing.

The hp/kw thing on the graph caught me out there, Benny's is laggy as well lol, peak power is awesome though.

I'll try and get it on the dyno in the next few weeks.

 

Pulled the dumps off today, the ams ones aren't really that much bigger to be honest, apart from the 3inch exit.

Looks like a first year apprentice drilled the holes in the turbo flange of the ams dumps. The holes are a bit off.

Had to diegrind the gasket as well as it covered some of the pipe.

 

ouch, no offence, but ide be a bit dissapointed with those chris. not much bigger at the opening which i htink is the most important bit. My dumps literally dont sit in any more than those flanges you bought off me.

 

exactly, in my opinion, the exit pipe is not the issue here, with 28rs exhasut wheel , they are already too big for the 4 bolt exhaust housing and are really stuffed in there .

I dont think that split dumps are the way to go when space is at such a premium, id rather have much lower restriciton at the expense of wastegate turbulance.

The divider takes up so much space in an already cramped area..

 

Can measure them later, but waste gate is pretty much the same and turbine exit is maybe 5mm wider in diameter.

I would of preferred bellmouth's but no one makes them for some reason?
I probably should of just got some custom ones with those flanges I got from you Nial.

 

I wouldn't worry too much about the size at the flange, as long as there is no major mismatch in size. The primary pipe inlet is larger on the AMS, which you confirmed by having to grind the gasket to fit. The wastegate pipe inlet looks a little smaller, but is still larger than the gate itself. Remember the transition into the turbine is as small as 15mm.

The last set of these I fitted to high flows, I removed the divider, just to give a bit more real estate in the packed housing.

Realistically you should be filling the turbine outlet at on the wastegate side to make the transition into the dump smoother rather than increasing overall dumps size. Hence why external gate turbo will make more power, and alot more with stainless billet turbine housings.

The 2 most important parts are the transitions to and from the turbine, theinlet which is rectangular and far from good. This needs to be a smooth transition like a header collector. You can buy inlet tongues for Holset and BW T6 turbos to fix this, or round inlet housings for other turbos like GT3* up garretts from companies like Tial etc.

The other imoprtant point is the outlet, once again,smooth transistion like a header collector. This can be acheived with new housing by filling and then porting smoothing the outlet. Not really feasible with used housings as they can not be cleaned well enough to have a proper adhesion.

Although the dumps aren't ideal, neither are the turbos. You will see power gains from these dumps over Npowers. I do agree that an open dump will give a greater increase again, purely because of the large turbine wheel jammed into that small housing.

 

theoretically a split dump with a long wastegate pipe is the best. I read alot about dumps before i made mine and they will tell you that an open dump with no divider or internal tongue is complete crap and the gains will be offset by the turbulance caused by wastegate gas flow.

In theory an open dump is not ideal at all, but as eric said neither are the turbo's, some turbo builders will tell you that they are badly matched, cram the exhaust side and have a narrow efficiency range.

Having said that, I saw suprising gains by switching to stock dumps over my n powers, 4psi boost increase with same boost controller settings. I wouldnt be suprised if stock dumps actually performed better than those AMS ones in the case of GT28RS stock trubos, but that is a pretty big call.lol


I think the time has come for me to take my dumps off and make another set. Ill see how good/quickly i can make them or get prices to have them made.

My dumps perform in practice, no doubt about it. 400rwhp at 17psi and not dropping off till the limiter

 

I was undecided wether to run the separator or not I ditched it on the npower's so might do the same again.

 

Once i make space in the workshop, im going to remove my dumps and duplicate them, i think there is a hole in the market, especially AUS for well priced 3 inch open dumps

 

Update:
AMS dumps fitted, total prick off a job.

New front pipes made with mandrel bends. Very nice work by the exhaust shop btw free plug for men at work exhaust Capalaba.

Car feels less laggy and a more lively top end (possibly just in my head?) , I'm hoping a touch up tune will yield some good results.

I have decided to replace the mufflers that are losing their stuffing next, then it's ready for the dyno, wont be long now.

 

i wouldnt say its in your head, they will be an improvement for sure !!

Ill transfer that money too, this thread just reminded me. sorry !!!

 

No worries dude I know your a busy man.

So when's the next dyno day Nial hint hint..