Engine/Transmission (1998.5 - 2002) Mach 1.5's and Towing - Not what I expected.

[PC12Driver]

PC12Driver,



My exhaust housing is 14 cm2.



Len

You might want to think about a 12cm housing. Think of it this way: you're re-gearing the compressor to drive harder at lower exhaust volumes (i. e. midrange rpms and mid throttle settings - towing). The smaller housing will "tighten" the turbo up and give you more low end and mid range rpm boost. And more boost for a similar throttle setting will result in cooler egts.



As a bonus, you'll gain some low end response back and clear up some off idle smoke.



The housing is what you use to tune the compressor to your application. The effective rpm range of the HTBG/14 is too high for your style of towing (as indicated by only 25 psi of boost). The 12cm housing will bring the powerband down 200 rpm or so, and you'll start getting boost where you use it (like maybe 30-35 psi instead of 25 on the long pulls). The 'BG's compressor is good for about 40psi, so you have plenty of room to go before getting bad boost.



The HTBG is rated for trucks with 350-425hp. You're on the low end of the scale, so you can easily downsize without any negative effects. Heck, there's guys running 12cm housings on the HTB2, so the smaller housing will flow plenty.



Increasing compressor size is not the answer. A larger compressor will have more aerodynamic drag (more pitch on the blades), so it takes more exhaust volume (more throttle) to get similar boost numbers at mid power settings. Great for high rpm/high power applications, but that's not towing. And since you're not even spinning the 'BG's compressor to it's full potential, a compressor upgrade would be a waste of money.



And for the guys that are about to jump up and down and say that the 12cm is way to small and egts will skyrocket, please read this thread first. Clmsnow's truck is running about 450hp and saw a decrease in egts by going from a 14cm to a 12cm housing. The HTBG's like to be driven hard. The long thread that lead up to Clmsnow's decision can be found here. The housing discussion starts about post #98, and really gets thick about #169. A lot of the misconceptions of smaller housings are brought up in that thread (and ultimately proven wrong).



Give they guys at High Tech Turbo a call and tell them what you're doing and see what they recommend. I'd guess that as soon as you say you tow, they'd suggest the 12cm housing. And, they've got a great exchange program if you want to trade housings ($150).



Your F1 injectors and the EZ will make a killer towing combo. You just need more boost where you use it.

 

[Diesel Freak]

hmmm



Hey Vaughn, now I know why a lot of the informed posters on this board have left.



BOOST PRESSURE ALONE IS MEANINGLESS!!!



Shoot, I have a COmpressor map for a stock HX35, and according to is, it is good for 48 psi..... butt, it craps out at 1800 engine RPM



The HTBG is too small for this application!!!!!!!!



Paricitic drag on a large comprtessor wheel? OMG, I have read it all now!!!!

 

[Diesel Freak]

Increasing compressor size is not the answer. A larger compressor will have more aerodynamic drag (more pitch on the blades), so it takes more exhaust volume (more throttle) to get similar boost numbers at mid power settings. Great for high rpm/high power applications, but that's not towing. And since you're not even spinning the 'BG's compressor to it's full potential, a compressor upgrade would be a waste of money.

hmmm so what you are saying is that with a large wheel, I am wasting energy by getting cooler air, at a lower pressure?



hmmm what if Density Ratio is the same?

 

[Fishin Guide]

hmmm so what you are saying is that with a large wheel, I am wasting energy by getting cooler air, at a lower pressure?



hmmm what if Density Ratio is the same?

There you go again with that new fangled modern talk! I had to laugh at that too. It looks like you are better off to make 10 psi more boost at the same volume. Oh make sure to add some heat to the compressed charge, it'll help with "effeciency"! :-laf



Dave

 

[PC12Driver]

hmmm



Hey Vaughn, now I know why a lot of the informed posters on this board have left.



BOOST PRESSURE ALONE IS MEANINGLESS!!!



Shoot, I have a COmpressor map for a stock HX35, and according to is, it is good for 48 psi..... butt, it craps out at 1800 engine RPM



The HTBG is too small for this application!!!!!!!!



Paricitic drag on a large comprtessor wheel? OMG, I have read it all now!!!!

Or maybe it's because of the sarcastic "know it alls" that think one dimensionally that full throttle is all that matters?

 

[PC12Driver]

hmmm so what you are saying is that with a large wheel, I am wasting energy by getting cooler air, at a lower pressure?



hmmm what if Density Ratio is the same?

Nope, not saying that at all. The point I am trying to make is that he's not even getting the most out of the turbo he has.



If the HTBG/12 can keep 450hp in check, why isn't the HTBG/14 good enough for 350hp? Seriously, I'd like to know.



My stock 35/12 can keep my Mach 2s and Comp on 1 below 1200* while towing in 6th all day long. My DZ/14 will run hotter. Why's that? Maybe the smaller turbo is more efficient with less drive pressure? Naaahhh.



So, if the larger HTB2 would be better, wouldn't a SP66 be best? That wheel is huge. It should be able to keep things just as cool at 10 psi as the HTBG does at 40.



He could try a $150 exhaust housing change, that WILL increase the air density into his engine (the HTBG is good for up to about 40psi in our trucks before you start to loose density from heat, per HTT, from real world feedback). Or spend $500 for the compressor upgrade that will help cool the top end power that he never uses when towing.



Do ya ever wonder why the bottom end of a turbo's advertised hp range also increases with compressor size? Or why Piers uses an HX35 with his "Towing" twins?



Bottom line: Len is concerned about his egt's while towing. His turbo is barely working hard at 25psi with the 14cm housing. The 12cm housing will drive the compressor harder at the rpms he tows at, and get more dense, useable air into the cylinders, which will lower his egts. He's not racing. I've been through a similar experience with towing and the smaller housing did the trick for me.



Ooh, but I am impressed that someone could work a big phrase like "density ratio" into this thread. I wish I could have worked that into my post earlier, then I could have been a cool guy.

 

[Fishin Guide]

So, if I understand you correctly, he needs more boost and more drive pressure?



How are these turbos rated again? 450HP? Is that on the dyno, empty, sea level, altitude, or with a trailer in tow.



This is the problem with "ratings" they are rarely correct for every application. Let's face it. when towing that much weight up a grade, his foot is gonna be near the floor. So, how does corking up the exhaust side help again?



There is clearly a point of dimishing returns. Some compressors just can't do what he is asking it to do.



BTW, I know of two others with this same charger with exactly the same issue. Both sold these turbos and went to different units and are much happier. And, the boost numbers are about the same or less than they were running before. They are laggier on the street, but with a load, they do just fine.



It's all about use vs design. Trying to crank up the pressure is helpful in some cases, but in others, there is only so much air available at any pressure.



Dave

 

[Diesel Freak]

the HTBG is rated for 400-450 HP... but for a gas engine!!!!!





NOT A DIESEL!!!!!!



on a Diesel it craps out at just under 300HP (flywheel)



The HTBG can move enough air to keep 300 flywheel HP under 1250F, but not 350 rear wheel HP... .



This is why he has EGT issues!!!!

 

[Diesel Freak]

A HTB2 might be a little large (rotor weight is a little heavy)... . a PS66 is way too big (plus it has huge surge problems)



a SP66 also weighs too much to be used at this fueling level.

a HX40 is great for this power level, and very reliable too. Just keep the engine above 1600 rpm.

 

[Diesel Freak]

Ooh, but I am impressed that someone could work a big phrase like "density ratio" into this thread. I wish I could have worked that into my post earlier, then I could have been a cool guy.

here is another one for ya



"excess air" :-laf

 

[Fishin Guide]

I know a guy or two that has that condition after some pie from Spiffy's! :-laf



Dave

 

[Diesel Freak]

Hmmm looks like I need to make more BOMBer events!!!

 

[Diesel Freak]

Posted this in another thread, felt it was applicable here also

FYI, I towed a busted DMX (broke his ATS transmission) from Spokane WA to Portland OR with my truck, and EGT was never an issue... . average speed was 60 MPH, ambient air temp averaged 100F, the AC was crankin, gear are 3. 55.



I was running between 1600 and 2300 RPM depending on if I was in 6th or 5th.



I ran 6th on the flats, and 5th on the hills. I was able to keep EGT below 1200F very easily.

Edit: I also have a boost controller... . allowing faster midrange spool of the HX40 at lower fueling levels

 

[PC12Driver]

the HTBG is rated for 400-450 HP... but for a gas engine!!!!!





NOT A DIESEL!!!!!!



on a Diesel it craps out at just under 300HP (flywheel)



The HTBG can move enough air to keep 300 flywheel HP under 1250F, but not 350 rear wheel HP... .



This is why he has EGT issues!!!!

High Tech Turbo lists the HTBG on their Dodge Cumminis specific product page for 350-425hp, 950 ft/lb applications. So, you're saying that they're talking about the gas powered Dodge Cummins?



Clmsnow's truck has DDIIs and a Comp, which is a combo that is pretty much a sure thing combo to get at least 430hp to the rear wheels. His max egts are about 1350* with the HTBG/12. But you do have a good point; I'm not sure if he was running gas or diesel at the time...



My stock turbo will keep my DDII's and an EZ under 1250. That's about 350hp. You're saying the 58mm Schwitzer perfoms worse than my 56mm Holset?



Regarding your 6th gear on the flats/5th gear in the hills, my DZ/14 is the same way. Get the rpms above 2k and egt's are nice and cool. With the stock 35/12 I can leave it in sixth a lot longer up steeper hills.



I asked the guy who did some work on my truck about why I seemed to lose some towing performance with my larger turbo. He pretty much explained things like I did in the past couple of posts and suggested that I try the factory turbo again. He was right; I put the old one back on and got my towing power back. He seemed like a pretty smart guy for someone who's shop was in the middle of a cornfield...

 

[Diesel Freak]

You're saying the 58mm Schwitzer perfoms worse than my 56mm Holset?

since you are "only" stating the Compressor Inducer diameter of the turbos it is very possible.



Post the Compressor Exducer size, wheel trim, Turbine inducer size, and wheel trim, then Compressor housing A/R, and exhaust housing size, then we can compare the two... . but the comparison fails without a turbine and compressor map.



2mm on the inducer of such small compressors as the ones you mentioned means very little by itself.

 

[PC12Driver]

since you are "only" stating the Compressor Inducer diameter of the turbos it is very possible.

Okay then I'll answer it for you. The HTBG outperforms my HX35 for top end cooling. I see 1450*+ with everything turned up and Clmsnow can barely tickle 1350* with similar power.



And knowing that my HX35 is good for 350hp, I'd say the HTBG would be good for something over that.



As I see it, the originator of this thread had a question about high temps while towing. I had a problem with high temps while towing. I was told by someone who has a clue (the guy in the cornfield) to put the smaller turbo back on and I'd get lower egts and some of my performance back for towing. He was right. And now I'm passing along my first hand experiences. Take a look back at your last few posts and tell me what you've contributed.

Post the Compressor Exducer size, wheel trim, Turbine inducer size, and wheel trim, then Compressor housing A/R, and exhaust housing size, then we can compare the two... . but the comparison fails without a turbine and compressor map.



2mm on the inducer of such small compressors as the ones you mentioned means very little by itself.

*Yawn* That's great, DF, really. I'm like, toootally impressed. Don't they miss you over in the comp forums?

 

[Joe Mc]

Post the Compressor Exducer size, wheel trim, Turbine inducer size, and wheel trim, then Compressor housing A/R, and exhaust housing size, then we can compare the two... . but the comparison fails without a turbine and compressor map.



2mm on the inducer of such small compressors as the ones you mentioned means very little by itself.

:-laf :-laf :-laf

 

[Diesel Freak]

hmmm well, I have had the itty bitty HTBG on my workbench, and took it down to parade rest. That and the results from a budy that uses his 3rd gen hotshot rig (with Juice Box... 366RWHP) and EGT was no better than the stock HY35. He now runs a HTB2, and is much happier.



oh, and for those who are still wondering why I compared the Horsepower of a gas engine and diesel running the same turbo... . it is all a matter of Air to Fuel Ratios... . a gas engine runs very well at 12:1-13:1 A diesel runs best at over 18:1 (smoke is very apperent at ratios less than 18:1).



If a turbo can make 400-450HP on a gas engine, it is basicly only good for 270-325 on a diesel (these are flywheel figures)



You can be impressed if you want... I know I am!!!

 

[Diesel Freak]

Okay then I'll answer it for you. The HTBG outperforms my HX35 for top end cooling. I see 1450*+ with everything turned up and Clmsnow can barely tickle 1350* with similar power.



And knowing that my HX35 is good for 350hp, I'd say the HTBG would be good for something over that.

using that logic, them my 61mm HX40 I should be able to just make 475 HP @1350F.



well, I wish that were the case!!!!!!! 1300F comes at a much lower power level than that.



Yes, the thread originator wants to cure his EGT problems. I am saying that with the way his truck is fueled, the big issue is that the HTBG turbo is too small for his fueling level.

 

[Diesel Freak]

Just to add a little documentation to this thread.



Compare this turbo S300 Generic which is only good for 230 to 370 smoke free, and piston friendly EGT on a diesel engine to to your HTBG...



I bet the HTBG comes up short... .