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Looking to get some grunt out of the old 6.5

pacificdrumma

pacificdrumma

Well-Known Member
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Hi everyone, I have a 1996 GMC 2500 HD that I am looking to soup up a bit. My desire is not to blow smoke, or tow 10,000lbs or have a tire roasting machine. I want to have a healthy running, clean burning truck with enough low end grunt to get up and go when I want, haul a little here and there, and maintain good MPG. I have had a drop off in power lately, and I think its time to replace the injectors (150k). I have made my own intake, own exhaust, and own turbomaster, but I would like to start upgrading to the "real stuff" so to speak. I have done some research, but ultimately I want to talk to people who have done the mods that I want to do, and see what you all have to say.

Exhaust- I'm thinking 4" Diamond Eye with 3" down pipe and 2.5" Flo-Pro cross over? I found the exhaust itself for about $240 and I figure about another $100 for the cross over. Good or not?

Intake- I like the looks of the AFE Stage II kit, I have no problems making my own, but I would like to purchase and install, not fabricate this time around. S&B makes one too, but not sure if I want something with an enclosed box around the filter.

Injectors- Here's where I need help. I know SSDiesel sells marine injectors, but I also know SSDiesel's reputation. I trust Heath, but I don't want to spend $1000 on injectors. I have seen some on Kennedy Diesel as well. So what are you guys running for injectors, and what would you recommend?

Turbo- Another big one. Currently have a new GM-4 with about 9k on it. It works well at slower speeds but my highway acceleration SUCKS. It will spool up as high as I want, and make no power. Im sure injectors will help, but I think a bigger turbo is gonna need to happen too. So the two main choices I have been looking at are the ATT and the Chinese HX40WII. I am hesitant abou the ATT because it has a pretty negative reputation on some other forums, but I also know many people like it. I have heard only good about the HX40WII as well, so not sure there. Whatever turbo I get will need to be able to work with the chip which will come after. I dont know if Heath makes a chip for either, or who does in general.

Chip- Now, the chip is the last piece of the puzzle. Heath, SSD, Kojo, Kennedy, and others all make tunes. I have heard about a 6 position Buddy chip which sounds ideal, but cant find a way to find out more.

Basically, I want to get to about 240hp and do it without blowing up my truck. What do you guys think?
 
I would get run the GM8, 4inch exhaust, skip the marine injectors, they aren't worth the money. Get a set of stock rebuilt Bosch injectors with 2300psi pop pressure, and an AFE Stage II. I run one. Works great. For what you are aiming for, I wouldn't go above a GM8. Especially if you want it smoke free.
 
If you stick with your turbo - definitely get the S&B - the open top AFE sucks hot air which is not what you want for a non intercooled truck. S&B sucks cold air from the ram air piping through the fender.

I would get it tuned by Heath (good luck with mine so far) - The Buddy chip is only for OBD1 trucks (as far as I am aware)

Then, I would go with the HX40w-ii with a custom intake into your stock closed box - it will just smoke a bit while it spools but at least you dont have to throttle back when passing a car on the highway because you're running your EGT's up to high. Its also a great bang for your buck.

For the exhaust, I just got mine from warp speed performance; they have everything including the crossover and downpipe or just get it off ebay... Its all Diamond eye anyway.

I'm with 6.5L on the injectors; anything is better than the miled out ones that you have although I did go with the marine set so I can't say if they make any difference compared to a regular set.
 
I disagree with these two gentlemen with turbo choice. If you're looking for better highway acceleration with minimal smoke, go with an hx35. It's right in between their recommendations and would be a great compromise between better highway acceleration and low smoke levels. Plus, if you want alittle more power, you can always hybridize it to a 35/40 and or get a bigger turbine housing. But really, there's nothing wrong with either of their recommendations honestly. I just think they are both a bit lop sided to one goal or the other personally. Good luck with your build!
 
The only difference with Marine injectors is the spray pattern is designed for continuous load at stead high rpm (as in running a boat) so as to not burn up pistons. There is no power advantage. You may get lower mileage. I have the Heath Marine injectors in my '99 and I see 16 mpg highway at 70 mpg with a Heath tune and the ATT. Everyone else with the ATT claims more mpg on highway. My only difference is the marine injectors.
 
Search for War Wagon's thread on dyno tests with the ATT and the HX. Lots of guys on here have the ATT with correct tuning and it rocks, so don't believe everything you read. Any turbo with tuning that isn't optimized for it is bound to be less than ideal.

Marine injectors, no, but setting up the POP pressures to marine pressures will produce a definite improvement. DON'T buy cheap injectors... you will regret it. They are the one part that can kill your engine if they take a dump on you.

Tune - you're going to need an OBD-II ECM reflash, not a chip. Forget about the buddy chip. Again, getting the right rune for your turbo is important; just upping the fuel rates will not get you the power curve you want.

If you built your own turbomaster, chances are pretty good you aren't very efficient, so that is likely part of your mileage issue.

I also don't see any life-enhancing mods, like PMD relocation, thermostat change/rad stack clean, gauges, etc. You might want to go there before trying for some bigger power.
 
My signature says too many new parts, heres why (lol). I bought the truck December of 2011. 137k and change, just hit 150k last week. Since 137k..
-NEW Grey stanadyne PMD mounted on a heat sync to the front bumper with #9 resister
-Reman stanadyne IP from Pensacola (I have now heard bad things about them, input?)
-NEW GM-4 turbo
-NEW 105a alternator
-NEW batteries
-NEW lift pump
-NEW glow plugs
-rebuilt starter

So no real mods for life enhancement yet, save for the PMD. As far as temp goes, the truck rarely runs above 200, and only when I get on it for an extended period of time. Usually it stays around 195.

I plan on doing gauges right before the tune, 3 pillar from glow shift, any good?



Thanks for all the input so far guys
 
I wouldn't go with the hx35. The turbine housing is still kinda small for a 6.5
Your cruise psi will be too high and likely so will the drive pressure.
Right now I'm on stock tune with the hx40II and have new injectors. Spool up is fairly quick and I get zero smoke.
My turbine housing is 14cm and would have no problem running a 16cm turbine housing for even more improvement on mpg
 
I dont think I will go with an HX35 because I have heard that unless its a stock truck, its too small and restrictive. I know that with the HX40, you can safely run 15+ psi without worrying about head gaskets because it flows better and reduces drive pressure. How does the ATT stack up in this field? I dont think I will be going with an GM-X turbo's.
 
Just got done doing some reading, 6.5L's thread on the BD quick spool valve, and War Wagon's thread on the HX40 vs. the ATT. It seems like the HX40 is better for street use, and the ATT is better for towing. I dont tow more than 1500lbs currently (mower) and dont foresee myself towing more than 10k ever. That said, which is better for my application? Intake, exhaust, injectors, chip and turbo is what I want to do. Sounds like stock injectors at 2300 pop is what I want, 4" exhaust, 2.5" crossover, legit intake, and a chip is whats gonna happen.
 
Even though I sell the S&B I recomend getting a K47 and an dry element filter. You can relocate the K47 to a "ram air" type where the air is dwawn from cold side of core support. I have some pics somewhere here of it. Raceday did it along with a few others.
Exhaust = Diamond Eye:thumbsup: And no other systems are not all DE anyway! DE is the only one I know of that has a ball & socket on the end of down pipe.
Xover = FlowPro ( I can get for $85ish) Mandrel bent one piece.
Injectors= German Bosch (if you can find them)
I sell the ATT so you know what I'd refer.
Welcome to the site and check my web site if you get some time.
 
You have a HD truck. Seriously a Daily Driver? I would lean toward it being more loaded than a daily driver.

First off you won't be disappointed with the HX40II or the ATT turbo. The above recommendation for the GM8 for smoke has some merit, but, leaves you with an asthma attack. All you have to do is keep your fuel settings low to keep the smoke down in the tune. You can also use the BD spool valve that 6.5L showed us to make the best of both worlds with the huge ATT. A temptation that is hard to resist. Just have to save coin for it.

I have a 1993 that runs clean with the ATT: it sees a lot of DD use now. I have a 6.2 injection pump on it pegged out so the fuel and smoke is limited over a 6.5 pump.

My 1995 has had both turbo's. I can't stand the factory turbo for ANYTHING! It simply cost me too much MPG when MPG was my bottom line in business.

The dyno has the turbo's dead even. The dyno doesn't tell you that under extended load the ATT had 3PSI more room before the boost sensor for the engine pegs at 17 PSI and the 1993 will hit 18PSI. Dyno only got 14 PSI out of it - just couldn't load the engine like a trailer pull up a grade. The HX40II would come up to full boost of 23 PSI on the dyno. I have the worst platform for turbo's with a 4" kitty and small 6.2 precups on the 1995. This said I feel the ATT pulls harder than the HX40II on the freeway or any time the engine gets over 2K rpm especially near red line. The HX40II falls off near redline and wants to open the wastegate. The ATT works harder with load that way a turbo should. The factory turbo is like a belt driven supercharger generating 6 PSI of boost with NO throttle!

You have to be careful who you get the HX40II parts from as the quality can vary. Blade count can vary in the HX40II turbo off ebay and the seller can (did) plead ignorance. It isn't cheaper when you finish buying other parts to get it installed and is a more involved install with getting it to work.

I have had many conversations with Dennis, the ATT source, and I will say he backs his kit up 100% and then some. The bad rep and character assassination on other forums is not deserved. The other forums do it to other innovative people as well. This is why Thetruckstop.us exists. A lot of the bad rep is from people's own ignorance and insisting on lugging the hell of of their 6.5. The 6.5 revs higher than the duramax and the Cummins, yet, people want to hold it below 2000 RPM at heavy to WOT and bitch about the smoke. (Just like they did with the factory turbo.) A revised shift pattern to raise the engine rpm with load clears up some smoke. Further the bigger turbo's have power in the upper RPM where the factory turbo chokes. The age old advantages and disadvantages small turbo vs. large turbo applies.

When you can keep a common rail Cummins behind you with a ATT equipped 6.5 I would say that is impressive enough to change driving habits/shift points. (I didn't say walk em - just not able to gain on you.)

Again both turbos improve power over the factory turbo. IMO the ATT has more quality control and support to back you up. The Kit form makes install a cakewalk without relocating batteries and fabbing/grinding vband clamp ridges off the compressor housing etc the the HX40II requires.
 
A good honest post above with with real data to back it up. I am saving up for the spool valve also.
 
Just FYI, my 4in exhaust from. FULL BOAR had a ball socket on the end of the downpipe. And I would not run the quick spool valve without headsteads on the ATT. With the regular housing, I could peg 22psi in a heartbeat. With the large housing, I have got it up to 18psi. That's it. As soon as I get head studs, I am going to probably swap back to the small housing unless the large housing can reach 25psi with more fueling
 
6.5L said:
Just FYI, my 4in exhaust from. FULL BOAR had a ball socket on the end of the downpipe. And I would not run the quick spool valve without headsteads on the ATT.
Click to expand...

Quick question, how much was the quick spool valve?
 
Burning oil said:
Quick question, how much was the quick spool valve?
Click to expand...

:idea: Time for a group buy to get the price down. Of course you would have to make a kit to relocate the accumulator or get it redesigned.
 
I like that kind of thinking WW. They are 10 percent off right now, but the missus will make me live in the truck for that purchase right now.
 
Yes, I have a heavy duty truck and yes it gets a lot of DD time :) Down the line, I will be doing shocks all around and bags in the back because it sure does like to squat. Doesnt help that I have the front leveled 5 full turns and didnt beef up the rear.

I want my truck to have the grunt to do whatever I want, I dont care so much about 0-60 time or acceleration, so I think the ATT is the better choice for me. Any good sources for the German Bosch injectors?
 
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