Interally Gated HX35WG

[Kansei240sx]

I'm running one of those E-bay manifolds that i have modified and re-welded/enforced etc...Its an HX35(Internally Wastegate) 14cm twin scroll exhaust housing.

I had thoughts about getting it nickel welded shut and running an external wastegate.

I was wondering if anybody had experience with larger internally gated turbos on the RB2x and if they had any boost creep/lag compared to the same turbo on an external wastegate. I know the wastegate port itself is about half and inch to 3/4th of an inch larger in diameter than the stock wastegate port on the T28, maybe even larger.

Should i weld shut the internal gate and run an external?orShould i keep it internally gated

[BoostFab]

i say run external gate. dont use the wastegate actuator that come with that turbo.that's what you would need to do to run external wastegate.tig welded it shut, it's under high temperature due to the heat, so do it right..

[gawdzilla]

dont have experience with the internal gate on a bigger turbo, but i know the ssac manifolds creep. so keep that in mind.. going external may not solve the problem.

how bad is it creeping now? it's just a sign to run more boost

[Cjmartz2k]

The DSM guys run internally 38mm gated ex housings on HX35 and HX40's all the time, but it's a proprietary housing to bolt on to their 4G63's, so it's not apples to apples. Also, that factory holset actuator is set to open at like 30 psi or something.

I think external is the way to go. You could bolt the arm connected to the flapper too to close it, but you'd have to make sure it's closed properly. I bolted my HX35/40 hybrid shut and it was fine. Welding is the better option though IMHO.

[Cjmartz2k]

Just a little info on your turbo from the DSM holset thread I think some of there HP numbers are a little optimistic, so take it for what it's worth................

HX35:

The 8blade hx35 has a 56mm compressor inducer. This is found on 1995-1998 cummins manual pickups. The compressor flows 52 lb/min according to the compressor map. The bolton BEP housing (0.55 a/r) is enough to push the limit of the compressor. There's several 500whp 8blade hx35 cars out there with the bolt on housing. It reaches 20+psi by 3500rpms in 3rd with 272 cams. Smaller cams would equal a faster spool speed in most cases.

The 7blade hx35 has a 56mm compressor inducer. This is found on the 1999-2002 cummins manual pickups. The compressor flows 60lb/min according to the compressor map and logged results from a member here. The bolton BEP housing with the hx35 turbine wheel do not SEAM to have enough flow to really reach the potential of 60lb/min. But many have logged over 50lb/min so far and seen 500whp. The stock hx35 12cm^2 twinscroll turbine housing is a t3 flange housing. This mated to a NON-divided runner manifold has produced a 132mph trap speed with a full weight 1g AWD. This is about 600whp. So the flow is there with the stock housing if you use a non-divided manifold. The spool speed of the 7blade hx35 is similar to the 8blade hx35 with 20+ psi by 3500rpms in the bolton housing and by 4000rpms with the stock housing with a non-divided manifold.

[Kansei240sx]

Thanks guys, When you talk about bolting the External gate shut, where are you referring to the bolt? Drilling a hole right behind the gate, and threading a bolt through the back of the plate onto the WG flap?

I've also seen some people use HKS wg actuators to drop the opening point on these turbos, so i just thought it might be a viable option.

Im using this as a circuit car so i want to keep the major engine components as simple as possible which is is obtainable (believe it or not).

I'm aware of boost creep on these manifolds, which is why mine is modified.

The external gate tubes on these are the wrong direction, so most people cut them and flip it around, i've done that, but im using a V-BAND at the area i cut it at so i have alot more flexability to run an external gate and not get stuck in one spot without having to cut it and re-weld it.

Also, assuming i go external gate, what size wg should be adequate? 40-45mm?