Put the screws to the HX40II on the rollers.

[WarWagon]

So I finally made the time to get the 1995 down to the rollers. I joined another forum's diesel dyno day. :sifone:

208 HP and 394 TQ. Was 66 Degrees F today.

At the end of my last run the boot blew off the intake at 22 PSI. I thought the radiator cap was venting while everyone else was landing from jumping out of their skin. Skittish... :rolleyes5:

Interestingly enough I have a near flat 200 HP from 2000 RPM till 4000 RPM at the wheels. IMO neither the ATT or the HX40II spool enough to matter below 2K RPM. From a stoplight stomp they light up at 2K RPM period. Steady load there is a couple PSI more below 2K with the HX40II. Switching from an ATT turbo to a HX40II WILL NOT solve a smoke problem! EGT's... Lets just say I burn off turbo blankets.

This is a 1995 Suburban with a 1986 Military 6.2 complete with Military 6.2 NA precups and 6.2 heads. Head studs, wrapped headers and crossover, 4" exhaust with 4" Dmax kitty. Mallory 17PSI 250 GPH lift pump. Tuned, Buddy 6 banger, like crazy to get the smoke down. 3.73 Rear and 4L80E. 4X4.

Thanks to Buddy for the loan of the turbo. :thumbsup:

About the HX40II vs. the ATT.
So far I have had to repair the intake twice with the HX40II for blowing out at the turbo and in the middle of the boots. (The ATT came out with a redesigned intake that I haven't touched on the pickup since install.)
The exhaust leak after the turbo is really bad at the v band down pipe clamps. See pic.
I have to blow the soot out of the air filter often from the HX40II exhaust leak.
IMO SOTP The top end pulling power although better than factory is not as strong as the ATT.
Opinion of two drivers is that the HX40II is slightly earlier to spool up.
Boost at lower load cruise is higher than it needs to be. About 6 PSI at 70.
Exhaust rattles off the inner fender liner as the downpipe clearances change from the ATT to the HX40II.
Although I scorched the ATT turbo blanket (it is still useable) I have had to replace the HX40II turbo blanket twice as the one I am getting is not as high of quality and the exhaust leak is doing them in.

Most runs were started at 2K RPM in 4th.

 

[NVW]

Thanks for sharing.

Why would a little noise of the boost hose popping off scare anyone?:hihi:

 

[JiFaire]

Thanks for sharing, indeed... this is one of the first times anybody has compared the two turbos on the same vehicle, and dyno tests rock. Your attention to detail is admirable; thanks!

The last missing detail here is the tune; Dennis has been making ground on better tuning that is really working well with the ATT, and Bill Heath has been doing some nice work there, also. Some of the other reports are indicating that the ATT and the HX respond differently to different tunes, so it might be a good idea for somebody else to replicate WarWagon's work using a different chip or Tune?

Thanks again for the report... well done!

(got an address for me to send a few rolls of Toilet Paper to the guys who got spooked by your dislocated boot? )

 

[Twisted Steel Performance]

Nice info, it is strange that the HP is so flat isn't it??

 

[6.5L]

Good torque numbers. A nice comparison. Good job!

 

[THEFERMANATOR]

Nice info, it is strange that the HP is so flat isn't it??

It looks to me like the tradeoff between the ATT non wastegated higher flowing exhaust, and the HX40's wastegated housing choking down some on the big end. The wastegated turbo when sized properly is going to do more down low, but once it gets into the wastegate opening territory it will begin to choke it back some. It also depends on how the fueling is set. I'm assuming that buddy maxed out his fueling starting in around 2000 or so which would also explain a part of it. The DS4 injection pump reaches peak fueling around 1800-2000 RPM's, and dies off some from there as it goes up simply due to it's design. So if it hits peak fueling down low and tapers off as it goes up, that could also be a part of why it stayed so flat as the loss in fueling as teh RPM's go up would keep it from spiking up so much.

 

[tanman_2006]

Says he is trying to keep smoke down so I almost bet tom has his fuel cut back some at lower rpms. Maybe the HP results are part of the NA precup limits

 

[orrum]

So what is my 6.2 NA supposed to have in stock horsepower versus a 6.5 NA versus a 6.5 stock turbo?

 

[6.5L]

http://www.thetruckstop.us/forum/showthread.php?34898-Diesel-specifications-good-info-please-view!!!

TRY THAT. SOME GOOD INFO. IF YOU SCROLL DOWN THEFERMINATOR CORRECTED A LOT OF MY INFO AND IS MUCH MORE ACCURATE. HOPE IT HELPS

 

[WarWagon]

Best we can tell is the NA precups are the challenge on this engine. The only difference is the Injector angle and precups over other 6.5's and that has required considerable tuning to overcome. The 1993 is fairly smoke free. Had I to do this engine over I would have obtained turbo precups. So I am not totally worthless - I can serve as a bad example.

The fuel is cut some at the upper end to keep the smoke down because this setup simply wouldn't burn it. Just put it to smoke and higher EGT's. This may be the flat HP cause. This was the same result with both turbo's.

I hope to retest with the ATT in place and also explore other tunes when available.

Again I am leaning toward the ATT from an install perspective being easier with nearly all parts included and the reliability: exhaust leaks and boots blown off. (I have enough other things to require attention under the hood without the turbo setup adding to the problems.) Around town driving I will re-compare esp. now that we have a mostly smoke free tune and bug free fuel system. The low end advantage can be big with the cooling fan locked in, the AC on, and 115 degrees out.

This has been at least a year of testing the HX40II. One last thing to add is getting 15 MPG freeway beating the best 14.x the GM3 gave me on the 1993. This was the highest MPG yet and yes CA speeds with a lead foot.

 

[Pepperidge]

don't know if you've tried it yet...but clean the boots surface area real well with your favorite choice of non residual cleaner...then spray hairspray on the inside of the boot, reattach and tighten the heck out of the clamps...this works wonders with boots being blown off...

 

[BigBearZach]

Those numbers aren't to much off of mine with the hx35 and a boost leak

 

[tanman_2006]

NV4500 vs 4L80 the stick usually wins on the rollers while a properly built slush box can out run a stick while still pulling nicely.

 

[turbonator]

Says he is trying to keep smoke down so I almost bet tom has his fuel cut back some at lower rpms. Maybe the HP results are part of the NA precup limits

last spring we pulled 225 rwhp with NA precups, maxed .310" IP and 16cm2 WH1C intercooled..... i think our biggest limiting factor was 300,000 km engine and leaky IP...not to mention the 4 hr drive heat soaked the engine, when we arrived we got on the dyno immediately......

 

[WarWagon]

last spring we pulled 225 rwhp with NA precups, maxed .310" IP and 16cm2 WH1C intercooled..... i think our biggest limiting factor was 300,000 km engine and leaky IP...not to mention the 4 hr drive heat soaked the engine, when we arrived we got on the dyno immediately......

Was it running clean or smoking good?

 

[turbonator]

Was it running clean or smoking good?

heres the video, all with a cell phone so the sound sucked so i dubbed music over it....http://youtu.be/s5mUokYrzDM

it was not very smokey, a puff when i floored it, but it cleared up fast, will know what kind of damage all the dyno runs did to the pre cups right away as we are pulling the motor to put a fresh one in a couple weeks, and we need the head studs so the heads are coming off... when i installed those cups, 11/2 years ago they had no cracks...

 

[WarWagon]

Now it gets good! From total 'sleeper' to inaccurate dyno. Guess they have a hard time believing a 6.2 can do this! :hihi:

http://www.cumminsforum.com/forum/arizona/559252-arizona-diesel-shootout-42.html

 

[THEFERMANATOR]

Now it gets good! From total 'sleeper' to inaccurate dyno. Guess they have a hard time believing a 6.2 can do this! :hihi:

http://www.cumminsforum.com/forum/arizona/559252-arizona-diesel-shootout-42.html

It's not that hard to believe. A healthy stock 6.5 turbo can put down around 150-160, so I see no reason why a 6.2 turbo shouldn't be able to put down 200 easily as evidenced by your dyno run. Then again many still think the 6.2/6.5 is a converted gas engine that belches black smoke out giving all diesels a bad name.

 

[Twisted Steel Performance]

Now it gets good! From total 'sleeper' to inaccurate dyno. Guess they have a hard time believing a 6.2 can do this! :hihi:

http://www.cumminsforum.com/forum/arizona/559252-arizona-diesel-shootout-42.html

Sounds like a lot of bickering is done there, good run for a fuel mizer me thinks!!!!

 

[vegtech]

The last missing detail here is the tune; Dennis has been making ground on better tuning that is really working well with the ATT, and Bill Heath has been doing some nice work there, also. Some of the other reports are indicating that the ATT and the HX respond differently to different tunes, so it might be a good idea for somebody else to replicate WarWagon's work using a different chip or Tune?

(got an address for me to send a few rolls of Toilet Paper to the guys who got spooked by your dislocated boot? )[/QUOTE]

I dont know what Bill did to my tune but the first time i had him reflash for the ATT it smoked like friegt train. i had to send it back cause i had an EGR code so i asked him to cut the fuel back some on the low end. Well now the smoke is gone but the power is al there. I happy with it. I wishBill sent spec sheets or something so you know whats going on and could give feedback but i guess its cause they dont want eveyone knowing what the tune is.