Engine/Transmission (1998.5 - 2002) Mild porting on the HTB2 - w/ Pics

[Eric Lee]

Mild porting on the HTB2 & Dump Tube w/ Pics

I just received my new HTT HTB2 to replace my PDR HX35. I rent shop space out in my old paper factory to TRE - Team Rip (specializes in transmissions for the Mitsubishi turbo crowd) Jon actually started by doing the turbos for this bunch of nuts and was present as I unwrapped the new turbo - he immediately noticed a few areas that need tweaking and is going to help me go through this turbo this weekend. I will be posting before and after pics of the areas that he deems basic improvements necessary on any High performance application.



In my search for the right turbo for my 2nd Gen towing application I ended up with the HTT HTB2 in 62/12. The II PS62 is from what I gathered a ported version of the same turbo - and after initial inspection the HTT has little to no porting and cost proportionately less. I don't know what porting and where II thinks is important, but Jon is really a brilliant guy with much turbo porting experience and I'll show you what basic improvements he deems rewarding.



-Eric

 

[LOtero]

oooooh interesting... . im gunna bandwagon on this one. .

 

[59Turbo]

where's the pic?

 

[Joe Mc]

Hey guys I anxious too but the man did say this weekend, it's only Thursday night for Pete's sake. :-laf

 

[59Turbo]

Hey guys I anxious too but the man did say this weekend, it's only Thursday night for Pete's sake. :-laf

Oops, my bad. I should be more observant when I read things... :-laf

 

[Eric Lee]

Htt Htb2 Before Pics

Here's the pictures of the 'as shipped' HTT HTB2 in 62/12 configuration.



I wonder what purpose the grinding on the outside of the exhaust housing had? Anybody know - was it necessary to chuck it into some machine for what operations HTT has allready performed - or- did Schwitzer do it?



-Eric

 

[Joe Mc]

Great! Now make sure to take the same pictures before you put it on after the port job is finished. So we can compare. Oooohhh, I can't wait to see I hate to rush things but, is it Monday yet? Where's those darn pictures:-laf.

 

[JoshThomas]

Any pictures of the ported turbo yet

 

[Bob4x4]

Here's the pictures of the 'as shipped' HTT HTB2 in 62/12 configuration.



I wonder what purpose the grinding on the outside of the exhaust housing had? Anybody know - was it necessary to chuck it into some machine for what operations HTT has allready performed - or- did Schwitzer do it?



-Eric

Possibly removing numbers so you cant go out and find one cheaper??



Bob

 

[Eric Lee]

Update 9.19.06

Jon said this turbo is really pretty nice as is - like I've heard here - the compressor housing could be extrude honed, but really - it's damn good as manufactured. Some of those types of improvements are only going to be noticed at the extremes anyway.



This compressor housing would not chuck up in his lathe - the angles he wanted to cut at the lips of both rings might have improved a little somethin' but... . it doesn't seem important enough to give it to my 3-fingered machinist. He'd probably do it right - but he's he IS missing quite a few fingers... .



Jon did some minor port matching and smoothed the path into waste ports only in the direction of travel. Attached pic. Other pic includes the original HY.



We got a little sidetracked here - I know it sounds a little dramatic but we're cutting a new cover for the wastegate chamber and reconfiguring it for an external dump tube. Should be interesting - I am researching the flanges and v-band clamps so I can incorporate a joint right close to a 90 at the new plate. That joint will greatly simplify initial fitment as well as future in and outs.



The 1 1/2" tube will exit below the truck and basically inline with the downpipe or maybe out the fender well - there's allot of room both routes. I don't think I'll have to wonder if my waste gates are open or not.



Think I gone over the edge? - Eric

 

[Eric Lee]

Waste passage plugged

Here's the point of no return - the original passage had to be plugged. The dump tube is going to be 1. 75" instead of 1. 5" - that's about the max that will fit, and there are some components available in this size. The hardest thing to find was the v-band clamp small enough. Most manufacturers of these clamps make them to order to customer specs.



-Eric

 

[Eric Lee]

Jon is working on a prototype CNC cut wastegate cover with added height for another 1/8" opening clearance for the gates and of course a hole for the dump tube. He has showed interest in marketing these as a kit with either the machined covers or water-jet or plasma cut from 304 SS plate.



I am leaning toward the exit right underneath the HX40 downpipe as that will always be in the same orientation with the turbo as the dump tube and could be supported at the far end by it.



I have sourced the v-band clamps and flanges as well as the tubing and elbows. I should have the prototype assembled and installed in the next week or so - if anyone is interested please drop a short note to www.teamrip.com



- Eric

 

[Eric Lee]

Tube done -

I finally found time - with the sun shining through my windows - to finish this new addition. I will clamp the two pipes together after final fitting. I have placed the joint at a position to allow me to swivel it and exit where it has clearance. I will be wrapping the down pipe and dump - maybe even turbine housing with fiberglass.



- Hear that??... ... .....



-Eric

 

[JFlagg]

Don't know a whole lot about turbo workings, but what does this dump tube do?

 

[Eric Lee]

Basically it routes excess exhaust pressure out of the turbine's wastegate - hot - side of the turbo and dumps it to atmosphere to prevent overboosting on compressor - cold - side. Usually this excess exhaust is routed directly back into down pipe. I figure it will increase my usable exhaust volume - good, make lots of noise at full boost - cool, and let me know exactly when my gates open - safe.



-Eric

 

[JFlagg]

Is this basically like a blow-off valve?

 

[jwilliams3]

Is this basically like a blow-off valve?

No its just an easier path for the wasted exhaust to escape through.

 

[johncameron]

Is this basically like a blow-off valve?

No not really, a blow-off valve releases compressed air on the intake side. The wastegate dumps extra exhaust not needed to spin the turbo.



John

 

[BDR]

Very nice work Eric. I'm quite curious as to the benefits to this set up you have going. Does this change mean the turbo is no longer gated?

 

[Eric Lee]

The gates still operate the same way - the path the excess exhaust gases take has changed. Instead of being directed through an internal passage of the turbo back into flow of down pipe, it 'dumps' directly to atmoshere.



Sounds illegal - probably something that will make someone 20 years from now gasp... ... ... I don't think she'll last that long.

-Eric