The 2H/12H-T/1HZ/1HD-T/1HD-FT Gturbo Alternative Tech Thread (12 Viewers)

[DarkHorse1HDT]

That lobster back might look pretty there, but flow is not going to be good. You've got a massive step at the entrance between the V band clamp ID and the pipe. Looks like 3" would have been a far better size.

That step up in size is going to cause extra turbulence and drag.

I've been wondering about that every time I see mention of a 4" dump pipe... is there any point if the turbo exit is only 2.5-3"?

@mudgudgeon - I remember you did it, from the photos it looked primarily in order to seperate the turbine and wastegate flows, but you also said something about creating an expansion chamber so there was no chance of backpressure on the turbine.

Is it just making the transition smoother than the V-band-to-pipe joint above that can reconcile your ideas with what @Dougal is saying?

While I've got you - your turbo is an -FTE CT20B with "a Supra 7MGTE front compressor housing to simplify connecting the intake."? Just the housing, still using FTE wheel? What is the difference in the housing?

(Sorry if I'm going over old ground again...)

 

[mudgudgeon]

your turbo is an -FTE CT20B with "a Supra 7MGTE front compressor housing to simplify connecting the intake."? Just the housing, still using FTE wheel? What is the difference in the housing?

Correct. 1HD-FTE turbo, supra front housing.
I swapped the supra front housing on as I had one laying around, and it's a little more universal fit, easier to run intake hoses.

 

[mudgudgeon]

[QUOTE="DarkHorse1HDT, post: 11806913, member: 118117"] @mudgudgeon - I remember you did it, from the photos it looked primarily in order to seperate the turbine and wastegate flows, but you also said something about creating an expansion chamber so there was no chance of backpressure on the turbine.

Is it just making the transition smoother than the V-band-to-pipe joint above that can reconcile your ideas with what [USER=23942]@Dougal is saying?[/QUOTE]

On my old HDJ81, I used a 4" bend from the turbo flange, but pie cut it to reduce it down at the flange for a better transition.

In the pic above, I've used a 3" bend from the turbo flange, stretched out to transition to 4", and also used a 2.5" bend to separate waste gate gases at the flange.
The bend I've used would give the 8" transition from 3-4" that gerg suggests.
My thinking was that a 4"dump means zero back pressure, and that there's room for gases to continue to expand. Not sure if there's any merit to the second point, but on both my HDJ81, and HZJ105, the turbo spools up fast.

My HDJ81 was very noisy with the 4" dump without mufflers, whereas a lot of guys are happy to run 3"exhaust with no mufflers[/USER]

 

[gerg]

Not that is a nice looking down pipe.

 

[mudgudgeon]

Not that is a nice looking down pipe.

cheers. There's a lot of hours in that fecker! I wish I did more reading before welding the O2 sensor bung in it there

 

[Mcreight911]

Effort v's gains if your below around 300hp 3-3.5" if aiming above 300hp 4" . Heaps of variables but to keep it simple those number are easy guidelines. I find it easier to do as mudgudeon has and section 2 pieces for the dump and add a splitter

 

[boosted105]

That lobster back might look pretty there, but flow is not going to be good. You've got a massive step at the entrance between the V band clamp ID and the pipe. Looks like 3" would have been a far better size.

That step up in size is going to cause extra turbulence and drag.

I would say the step between the 3 inch to 4 inch is overcome by having a 4 inch dump pipe that goes right back to the gear box.
As soon as I took it for a drive I could tell the difference in response and lack of black smoke compared to the old set up.
Going to the big dump and 8cm rear was the best thing I did. There is no tight bends in the dump and I haven't got a boost gauge on yet but you can tell the car isn't struggling or choking. Screamer sounds mint as well.

 

[mudgudgeon]

I would say the step between the 3 inch to 4 inch is overcome by having a 4 inch dump pipe that goes right back to the gear box.
As soon as I took it for a drive I could tell the difference in response and lack of black smoke compared to the old set up.
Going to the big dump and 8cm rear was the best thing I did. There is no tight bends in the dump and I haven't got a boost gauge on yet but you can tell the car isn't struggling or choking. Screamer sounds mint as well.

Have you got a pic of it all fitted up?

 

[boosted105]

Have you got a pic of it all fitted up?

I will get one tonight, we finished putting the car together last night and had it's first full drive. Looks really good.

 

[mudgudgeon]

Cool. It's a good feeling doing that first drive hey!

 

[boosted105]

Yeah it was good to get it back on the road after a month or so, can't wait to get the new gauges on and give it a proper tune. Hopefully add some fuel up top.

 

[Dougal]

I would say the step between the 3 inch to 4 inch is overcome by having a 4 inch dump pipe that goes right back to the gear box.

Fix that transition and it'll be better.

 

[boosted105]

Not enough room to fit a long transition with 4 inch, I am not to phased about that little jump at the start.

Much better than the 2.5 inch dump on old setup.

 

[Dougal]

Not enough room to fit a long transition with 4 inch, I am not to phased about that little jump at the start.

Much better than the 2.5 inch dump on old setup.

It is the little jump at the start that is the problem. It creates recirculation and turbulence in a ring right around the turbo exit. There is plenty of room. It's smaller than the pipe you've got.

 

[boosted105]

It is the little jump at the start that is the problem. It creates recirculation and turbulence in a ring right around the turbo exit. There is plenty of room. It's smaller than the pipe you've got.

Length wise the dump is already nearly hitting the aircon lines.

 

[boosted105]

All on

 

[Dougal]

Length wise the dump is already nearly hitting the aircon lines.

It would be shorter and tighter radius with a smaller entry.

 

[boosted105]

It would be shorter and tighter radius with a smaller entry.

Aside from the fact that I can't see that step up making a massive difference opposed to the fact that it now has 4 inch to flow compared to 3.

I simply wanted a 4 inch dump and in stainless. And it looks good.

 

[boosted105]

Anyway, back to turbo performance.

Its a weapon to drive and only running 25psi at the moment. I will have to do some proper testing for response on the weekend but for anyone with a 12mm pump I highly recommend a 20g and no smaller than the 18g. Make sure you get the 12 blade rear and 8cm housing as well if you don't want it to choke up top.

 

[Wildnlost]

Anyway, back to turbo performance.

Its a weapon to drive and only running 25psi at the moment. I will have to do some proper testing for response on the weekend but for anyone with a 12mm pump I highly recommend a 20g and no smaller than the 18g. Make sure you get the 12 blade rear and 8cm housing as well if you don't want it to choke up top.

Nice work. Pipe fabrication is sweet. I am running a TD05-18g with 7cm and a few supporting mods. 3” off the turbo all the way back full muffler and resnator. Happy at 24psi. No comparison to stock is it? My truck with warped block and leaking head gasket is way stronger than stock. Pulling the engine soon for repairs.....then it should really rip.
Cheers