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

[Forrest Nearing]

it'll paint the underside of the truck and the tailgate black w/ soot

 

[JFlagg]

If you were worried about the soot under the truck, couldn't you just tie it back into the downpipe? Or would this negate the whole mod? It definitely looks interesting, though I don't know enough about turbo workings to know the advantages of this mod. Seems like alot of work, does it improve performance enough to notice? Put i t in laymans terms for me guys... . :-laf

 

[isb360]

Eric's theory for dumping wastegated gases to atmosphere rather than routing them back into downpipe was to "increase usable exhaust gas volume". I am not sure about that. The aerodynamic choke point of the system is the turbine wheel itself. The wheel extracts energy from the gases passing through it (thus lowering gas temp and pressure) to drive the compressor wheel via the common shaft. Dumping exhaust into the gas stream downwind (so to speak) of the turbine wheel should result in no change to how it works. Am I making sense?



Not to say that the whole thing wouldn't SOUND cool, though...



Tim

 

[NoSeeUm]

Eric's theory for dumping wastegated gases to atmosphere rather than routing them back into downpipe was to "increase usable exhaust gas volume". I am not sure about that. The aerodynamic choke point of the system is the turbine wheel itself. The wheel extracts energy from the gases passing through it (thus lowering gas temp and pressure) to drive the compressor wheel via the common shaft. Dumping exhaust into the gas stream downwind (so to speak) of the turbine wheel should result in no change to how it works. Am I making sense?



Not to say that the whole thing wouldn't SOUND cool, though...



Tim

It would sound cool, and be useful for tuning. You would know when you were on the wastegate and how hard.



I think you could get rid of the soot / noise and still maintain the turbine back pressure goal by just flex piping it paralell farther down the exhaust pipe and tieing it back in.



Jim

 

[Eric Lee]

I'm not sure about the soot thing - I believe I'll find out.



I am most concerned about the excess pressure on the head actually. This new turbo could easily boost way higher than I want - this mod will allow me to monitor the wastgate/boost with my ears.



I'd like to know when to let up a little without looking at my gauge. It's on the pillar - but I lost my left eye as a kid so the last thing I should be doing, with my foot in her, is to look away from the road with my good one.



I can't believe the pullers aren't doing this already -



- Eric

 

[NoSeeUm]

Eric's theory for dumping wastegated gases to atmosphere rather than routing them back into downpipe was to "increase usable exhaust gas volume". I am not sure about that. The aerodynamic choke point of the system is the turbine wheel itself. The wheel extracts energy from the gases passing through it (thus lowering gas temp and pressure) to drive the compressor wheel via the common shaft. Dumping exhaust into the gas stream downwind (so to speak) of the turbine wheel should result in no change to how it works. Am I making sense?



Not to say that the whole thing wouldn't SOUND cool, though...



Tim

The turbine itself works off of differential pressure. If you raise the turbine downstream pressure (back pressure) then total differential pressure will be less. This is mostly pertanent when the wastegate opens and dumps the much higher (hotter) energy and higher pressure gas right at the turbine outlet.



But like you say, that is more or less the entire point of the wastegate to begin with. Which is to reduce turbine Hp output and control boost. I would think there is a possibility of reducing drive pressure some what at any rate.



I can see Eric's goal. Although it would be difficult to compare performance unless he does it both ways.



Looks like very nice fab work. Oo.



Jim

 

[2broke2smoke]

but isn't he trying to reduce drive pressure AFTER the choke point?

 

[NoSeeUm]

but isn't he trying to reduce drive pressure AFTER the choke point?

Not sure what you mean by "Choke Point". Drive pressure is the pressure in the exhaust manifold just upstream of the turbine.



Jim

 

[Cooker]

I can't believe the pullers aren't doing this already -

EEP was venting the wastegate into the atmosphere many years ago. I don't know if it is still commonly done or if for some reason they got away from it?

 

[Eric Lee]

I finally got the new turbo on - I had my VP44 go out and I had to get the tools out anyway. I haven't spooled her up high enough to open the wastegates but she's a whole different ride. I think I read here to let a new turbo break in a little.

I forked over the extra for a HRVP44 from II - so I'm sure most of the power is from that. I'm absolutely amazed at how much more power she's got. Holy crap.

The new turbo and it's down pipe/dump tube went in perfect - the hardest thing was getting the old down pipe off the rest of the exhaust system. I unbolted it from the turbo and used a air chisel to 'grab' the bottom of the down pipe and force it forward and off. I ended up putting a hole or two in the old pipe but it was getting old and late.

I also went back to the OEM filter box with a PG7 filter. I don't think the open shield type filter boxes are the right thing to do. To much hot air. I also put a PSM hose into the cowel area and put back the OEM tube into the fender. As well as pressure washing and refilling radiator. Also re-routed the oil bottle to avoid the oil and subsequent clogging of the radiator.

I am truly happy with this set up. The only thing I worry about is if - or not - I set the waste gat actuator low enough to be able to install a boost elbow to adjust boost now that the turbo is buried in the truck. A 50# actuator is not easy to change on the bench let alone in the truck. If anyone has a suggestion - I'm all ears.



- See you at Terra Haute - Eric

 

[rivercat]

no mention of sounds any? same as before ?

 

[Eric Lee]

Turbo is in and everything works -

I am pleased with the whole upgrade - boost comes on strong and quick. The dump tube might be kinda novel and who know if it adds any power. I like the raspy note it reports. It's nice to know without looking away from the road where my pressure is at.

The turbos actuator was opening at 36 and I installed a boost controller that boostcontroller.com has an exclusive right to. The unit is made by Hallman - this particular unit is a prototype that is being developed for us diesel people. Gas motors don't make this kind of pressure - and they don't run on detonation. It's a ball and spring type and after installing it last night I ran it up this morning and she went to 40 and never wasted so I need to adjust as I go to get 40 - 45 pounds. It mounts in the wheelwell and is easy to get too.



I hope to meet some of you in Terra Haute - it's a long haul for me - 6 hrs. That's what I want to do but dinner dates, girl friends - you know - they just don't understand.



- Eric