I have an Evo 1 (2g DSM style 4G63), and I'd like to ask for some input before I go forward. Divided turbo manifolds are very rare for our platform (or very spendy), but I came across this super rare gem, a divided and cast manifold that suits the 4G63 and a T4 turbo. The problem, however, is that the wastegate flange is in such a spot that the wastegate would interfere with the turbine housing, there is no way to mount both.







I have a 7-blade Holset HX35 with 12cm divided T3 housing teed up (it does need a new internal wastegate, I've been delaying this), with a T4-T3 adapter plate to make it work. My issue is with boost control - my first option is to either weld a divider to the wastegate flange and bolt on a block-off plate, and run the Holset on its internal wastegate. I know this isn't great for power production, might creep due to the 19mm size (see the housing on the right for port size), and the wastegate only vents one pair of runners, so a pair of cylinders might run lean.




My other choice is this little pipe that bolts to the manifold and moves the wastegate off to the side - tight fitment, but possible. The issue here, is I don't know if I would lose the twin scroll effect by having a shared route to the wastegate. I would still weld the wastegate port to the divider, but use the pipe to a 38mm Turbosmart Ultragate that I have sitting around.




I know I could slap a IWG T4 EFR on it and make magic, or a tubular manifold that divides the pulses completely, but I'm a broke student (I did buy a $159 found-in-a-dumpster-Holset, after all), and I believe this manifold can really shine. Response is huge to me, and a cast manifold can probably outspool a tubular manifold by a good margin due to the shorter runners, the stored heat in the cast piece and possibly smaller diameter runners. My setup is ready to go otherwise.

What do I do?

 

Have you gotten this to work yet? Also, wouldn't the single EWG somewhat defeat the purpose of twin scroll?

 

I haven't installed things yet. I want to have the plan sorted out and all the parts available so the car won't be on jackstands for months when I go ahead with it.

The single EWG can work perfectly well if the scrolls are divided up to the wastegate valve itself. Mine has the undivided pipe, I'm hoping someone can tell me how bad that will contaminate the streams or slow down spool.

 

Anyone?

 

weird that it is a TS manifold, but merges the two halves with a non divided wastegate. This essentially negates the twin scroll design. Simply put, won't work as a true twinscroll since they are not separated.

 

This is an example of a design that falls short. The only way a single WG is compatible with TS is if each side of the WG port remains divided all the way to the valve. That is a tricky feature to implement. As this manifold allows each side of the TS collector to pressurize the other via the WG port, one can only guess at the impact the parasitic losses the turbulence will create. It's a bit like a trumpet designed such that its exit is plumbed straight into the **** sphincter of the person playing it.

This is one of those 'performance' parts that I wouldn't bother installing even if it were given away for free.

 

If response is huge to you i wouldn't be using that holset turbo. That thing will be terrible with that manifold. Holset turbos belong on trucks
Why not stay stock frame?
Whats your power goal?
A stock turbo setup will flog that dinosaur in every way

 

Why not go with an Evo 3 16g, or an FP DSM stock frame upgrade?

 

I figured. Thanks for the input, I think the undivided tube is off the options list now.

Haha, I like the analogy. This manifold is a replica (albeit improved) of an HKS manifold from the mid 1990s; the original's wastegate was even more impossible, plus the runners were divided all the way up to the turbo, except for the last 3/4" of the manifold. I have NO idea what HKS was thinking, but it ruined any chance at spooling quick. They made good peak numbers, though.

I contacted a fabricator to get the manifold divided to the wastegate flange divided, and to see if he wanted to take on the challenge of making a relocating tube that was divided as well. I hope he likes a challenge

I have a FP68HTA on my car already, and us DSM/Evo123 guys locked into single scroll without a $1000+ manifold. I used to believe the Holset was garbage, but discovered that when they're well set up on a DSM with a divided manifold and good tuning, nothing touches them. I'd like 450/450, with 300 ft.lbs by 4000 RPM on my 2.0L, stock-frame stuff can't do that.

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