ATT and KOJO tune for my 97

[Turbine Doc]

Buddy I've seen you often say the ATT is slower to spool, what comparison set up are you using GM turbo with 4" vs ATT with 4", or are you comparing GM vs ATT when running Banks exhaust. My Banks exhaust was marginal even with my GM-8, I never tried Banks with my ATT I had sold it by then, actually traded it off for some labor offset on my project engine.

My experience GM turbo with 4" Heath exhaust and ATT same exhaust showed marginal delta between the 2 when I was flowing with my IC, once I removed the IC I have no delta, Matt B observed my boost gauge as have several others, we aren't seeing any lag this vehicle. What are you calling slower boost development and what constitutes lag to you, are you saying peak boost does not build as fast ???

Yes I'll agree to that, but dare we go down the road of cfm vs peak boost yet again (lets not) my 0-60 time or acceleration in general has not suffered one iota by seat of pant.

Against a timed event running against a tree and chronometer at a track possibly a delta, but ATT has never been marketed as a "drag race turbo" your references to lag, slower spool put folks at odds with the turbo, I've gotten multiple PMs asking about your reference.

Of the folks that I have given guidance to about the lag/slow spool references that eventually bought them, not one has come back to me "Hey TD this turbo is a dog, my acceleration sux", not one person who has ridden with me says this thing really bogs at the bottom end, my boost development looks very linear more APP more boost, what is missing is the slowing to build boost at 2200+ rpm one sees with the GM turbo.

The ATT has bigger wheels, and peaks at a different rpm than the GM turbo, this does not equate to less air for a given rpm because the 2 boost pressures don't match at the same time.

Terry reason I ask about what type of muffler you have is because if it is cross flow like the Banks setup I ran with was you may have issues, I don't know if anybody running a 3" exhaust with straight thru flow muffler has installed one yet, yours may be the 1st.

 

[TMHark]

So it sounds like I may need to dump my NAPA "big truck" 3 inch muffler and go straight pipe or perhaps "cherry bomb" style (showin' my hot-rod age here) to test it out. I'll try it muffled first and watch EGT, boost etc.

I live in the middle of a thoroughbred horse farm and can't shake the windows and spook these ijits every time I go by!!

 

[Turbine Doc]

When you get it try as is 1st, it will be another configuration/data point the turbo itself if you have to go straight flow or "cherry bomb" will keep the noise tolerable.

I know those mufflers well myself from back in the days when I could not afford a replacement factory muffler, and young enough to appreciate the cool factor of V-8 muscle power making cherry bomb rumble; I still know how to do a point gap & dwell adjustment, and probably if asked could put in a set of "performance curve flyweights" in a distributor :thumbsup:

 

[great white]

When you get it try as is 1st, it will be another configuration/data point the turbo itself if you have to go straight flow or "cherry bomb" will keep the noise tolerable.

I know those mufflers well myself from back in the days when I could not afford a replacement factory muffler, and young enough to appreciate the cool factor of V-8 muscle power making cherry bomb rumble; I still know how to do a point gap & dwell adjustment, and probably if asked could put in a set of "performance curve flyweights" in a distributor :thumbsup:

Yeesh, that takes me back

That reminds me I have to order a petronix module for my 62...:rolleyes5:

 

[TMHark]

Those were the days

72 Firebird rally Espirit, 400, headers to cherrybombs (they actually bolted right to the headers), holley 750, ram air heads, hot ignition and advance kit, slap shifter and race valve body, could get rubber in any gear (even with crazy high gear ratio, high two's!!)

*I decided to edit out the crazy stunt listed just in case the statute of limitations hasn't run out on being young and stupid!*

Thank God no one got hurt. Maybe that's why I play with trucks now!!!

 

[Turbine Doc]

Remember "shopping for performance parts" at the junkyard, nobody could afford the cool stuff in Car craft Jegs & Summit at their infancy & only for the rich guys so we looked for wrecked performance cars for our performance parts dual plane intake manifolds, W-30 Olds heads, 6 pack carbs, Carter AFBs, Holley spread bores, vacuum secondaries kicking in those were days when one could claim bragging rights about having a really bad ass vehicle you built, vs the tuner you buy now some programmer thinks is good for your ride, so that not much different from vehicle A to B nowadays.

 

[great white]

Remember "shopping for performance parts" at the junkyard, nobody could afford the cool stuff in Car craft Jegs & Summit at their infancy & only for the rich guys so we looked for wrecked performance cars for our performance parts dual plane intake manifolds, W-30 Olds heads, 6 pack carbs, Carter AFBs, Holley spread bores, vacuum secondaries kicking in those were days when one could claim bragging rights about having a really bad ass vehicle you built, vs the tuner you buy now some programmer thinks is good for your ride, so that not much different from vehicle A to B nowadays.

Yup, many a cop car part found it's way on to a couple of my rides....

 

[buddy]

I dont know why you always complain about people using the lag term or I try to say spool slower instead to prevent that stuff. It may sound negative but its just the way it is.

Comparing GM4 to ATT on same 4-5" exhaust.

GM4 I have 20 psi quick and no black smoke, maybe a puff. Exact same exhaust and PCM program with ATT, HUGE THICK DARK BLACK cloud and boost builds slower.

So IT SPOOLS SLOWER, thats what larger turbines do. Its not a problem, but yes when I had the Banks exhaust the ATT WOULD NOT EVEN SPOOL past 5psi, LOOOOONG black trails of smoke.

Compared to GM4 on banks exhaust and no smoke at all and 20psi boost. So I am not complaining, but be realistic, it spools slower there is no physical way it can spool as fast. That doesnt mean its not better. Even Dan commented about it takes more RPMs to get the ATT up on boost, its how it works

There are ways to lessen the black cloud. Your PCM program probably idles at 11 cam degrees advance at idle and maybe you have 700rpm idle. OBD1 trucks came with anywhere from 4.5 to 9 degrees advance at idle and between 562 and 600rpm idle with automatics, 694 for manuals. I have a preference for where I set idle and advance for comfort/driveability and its not as high on my daily driving program.

 

[Turbine Doc]

Reason I "complain" if you want to call it that; is because folks tend folks fixate on that one word.

When you post it, as you do folks shut down and fail to ready any further, after that often there is no way for you to show the fact that marginal slower rate of acceleration differences between the 2 turbos has no net effect upon the vehicles acceleration or performance which everyone thus far who has installed one will attest to.

How about starting with the positive rather than the negative, or adding in variables as above "when I installed my ATT OBD-I programmed the way mine is set up it does X", what you describe is vehicle specific to yours, mine being OBD-II with a common enough reflash program to acquire, does not perform the way yours does, nor will it spool as slow or make plumes of smoke you describe. I've yet to see a report other than yours with your setup that complains about a major low spool from the rest of those that have installed the ATT, several folks have had issues but those also turned out to be specific instances with underlying mechanical problems.

If I choose to stomp from a standing start it will puff the ATT comes on line shortly thereafter (in blink of an eye) I'm accelerating and puff of black smoke clears, and I'm pulling harder @ 2-10 psi with the ATT than the GM-8 ever could, if I'm @ 10 psi I'm over 85 mph headed fast to 100mph with 12 psi; my GM8 required 15+ to do that.

Without IC or WMI you weren't going to do that for long and you were stressing the crap out of the engine, on a cool day 80F or so I can run 12-13 psi boost without a high IAT defuel but not enough highway or safety margin for 100mph runs, not possible with my GM-8

In my original replacement turbo I also point out there was a difference in turbo acceleration & even called it lag, it's there, is it enough to mention without some qualifying remarks I don't think so, maybe you choose to disagree, and when you point out the lag or slow to spool I'll add the qualifying comments as well if that is complaining so be it.

Words & phrases can have an impact, look at the rukus started by the inference that since it was cast in China running it was risky to put it on a vehicle, 2 years later my data proves otherwise yet it was necessary to step in and set the record straight, GM Guy said now that he knows the full story he can get behind the concept the made in China bothered him so he quit looking at it.

My "complaint" is that a slow to spool comment without the rest of the story may put someone who might be interested in one off from it, I don't have all the other stuff Buddy & TD do maybe it won't work in my truck.

It will, it does, I even ran a ATT with a stock program by accident it topped out at 9 psi, 90 mph was top speed plenty for most folks, it just runs better with rechip/flash and all other stuff we add to go for the gusto makes it more better as you know.

 

[buddy]

What, you want me to preface my posts with a qualifier, sounds like a similar request made in the past, but no sir, this is not just opinion, its fact. Maybe we have different definitions of a "puff" of smoke. I can make a "puff" so black you can't see behind you, and its generally large enough to obstruct any view behind you. Sure its only for about 3 seconds, but Im saying I dont get that at all with the GM4.

Same exhaust, same program, more smoke on ATT, this absolutely means its has less air upfront because it SPOOLS SLOWER. No matter what you change it will be that way. Doesnt matter what you do with programming, unless you just really limit fuel but then youre going backwards. If you lazy foot it sure there is no difference, or even just half throttle perhaps you dont get the black cloud. Or maybe your GM8 was crappy. I have done a lot of exhaust and PCM configurations testing this. I have done a lot of testing. This is not some theory. I will go as far as saying a homemade TM doesnt boost as well off the line either unless its really tight. Going from vacuum system to TM, not as good performance. I had more air faster, meaning GM4 spooled faster with vacuum system holding the wastegate shut compared to a spring set to a max of 17ish psi and 4psi at 75mph cruise. I have done several configurations of turbos and exhaust.

I would never recommend an ATT with stock programming, because not all stock programs are created equal. Someone might get it and have 5* advance and generally just way less advance throughout whole stock program than yours. So you cannot qualify your recommendation on everyones configuration. The PCM In My Opinion is better bang for your buck. The PCM being more bang for your buck is my opinion and I am willing to say that.

When an ATT WILL NOT WORK with a Catalytic converter or soot trap, you need to tell people that too. People with them will not be happy, trust me.

I like the performance of the ATT, I have never said different, but the fact is, it spools slower than a GMx, and if people wouldnt jump in to defend it and try to rephrase to make it sound different then there would be half as many words on this subject.

 

[Turbine Doc]

No need to get up on governor Buddy I'm not.

Never has it been told that ATT would work with soot trap, and not even sure it will work with Terry's 3" system we are going to find out, it can and does work with a stock program with 4" exhaust sans cat good point to bring up I forgot that, I also had h/o injectors that is also another variable for me, I don't remember if I was IC'd then another variable, never have a left large lingering trail of smoke you describe even @ full WOT, it puffs GM-8 did not; that also I'll agree with.

Consider the audience, guys that have seen smoke from a tweaked Dmax, Stroke, or Cummins and don't want it will fear that as a risk from your description, per your description also you have somewhat modified programming is that a consideration to your volume of smoke ?, my GM-8 nothing wrong with it, it is on a members vehicle as we speak and he is happy as a pig in mud with it.

Heck some guys will be disappointed in lack of smoke as it hits it and clears very fast, I've had maybe 7 TTS members ride in it now, none have said wow this thing smokes like crazy or watching the boost gauge have commented on a lag.

Is there a difference from GM-8 to ATT yes, on bottom GM-8 spools better, on top ATT outgrunts the GM-8, small turbos spin fast yes, to a negative detriment no; GM-8 is too big as well it required a WG & WG flow path/restrictions to get it moving which kills its top end capability.

So if you are opposed to adding disclaimer as I said above I'll fill in the rest of the story and we can both get long winded yet again, makes no never mind to me. If you are looking for a it spools slower from me, okay it spools slower you are right, feel better now ??? I'll preface my disclaimers with that also, Buddy is right it spools slower but,

Can we now :grouphug:

 

[buddy]

Thank You, ATT is better than GMx, but it spools a little slower.

It should work OK with 3" straight pipe.

Ive done 3" Banks system, you know how that sucked (unacceptable 5psi max) with soot trap and baffled muffler. It was so bad, I was so annoyed, I ripped it all off the next day, so no testing with just muffler or straight piped 3".

I did 4" straight pipe, worked awesome, would jump to 14psi and drop and hold like 10psi but really really loud

4" with large Donaldson catepillar baffled muffler, lost like 1-2psi boost 12psi max, and didnt muffle much, but was alright

4" with 5" Aeroturbine muffler and 5" exit, worked great, no loss in performance, didnt muffle much

4" with 4" Aeroturbine muffler to 5" Aeroturbine muffler and 5" exit, works really well, muffles OK and I think works better than just one aeroturbine muffler. So the in series claim they make is for real. I would highly recommend two AT4040XLs (or one AT4040 and one AT4040XL) in series, but expensive, looks cool though.

I'll be putting a small straight thru 4" chambered muffler in place of the 4" aeroturbine soon to test with the 5" aeroturbine, and hoping I dont lose much performance but its gets quiet. I dont like smoke and I dont like it real loud, I know Im not normal.

 

[Detroit Dan]

Seat of the pants, I think my GM-X (8?) turbo spooled quicker and caused my truck to be a little bit quicker off the line. The ATT did seem to take away a little of my bottom end 'snap', but it gave it all back and more at the other end. Which matches up with my experience drag racing a few quicker trucks, as I posted elsewhere-I sit around for a while puffing black smoke while they drive off, but once my big turbo clears it's throat and starts breathing, the smoke mostly goes away and I start reeling them in, with much better acceleration through the second half of each gear. This is totally what I expected from a bigger turbo, to get the advantage at higher rpm and fuel flow. It's a bigger turbo, after all. Only makes sense it would perform that way.

I should mention that I did the ATT several months prior to the tune.

I don't know as I would use the term 'lag', at least not in the way I understand the definition. But it will spool slightly slower at lower rpms. I like to use the breathing metaphor. I used to race a big block Chevy, there was plenty of smaller high winders that could give me a run for my money while I was wasting time either spinning tires, lifting the front wheels, pulling the chassis all out of shape, but eventually the big block 'started breathing' and acceleration improved exponentially. The faster it went, the faster it could accelerate. By 'breathing' I mean drawing in volume of air and pushing it out the other side. Same theory as the turbocharger, really.

I like the smoke, I get a pretty good cloud for a few seconds. The only bad thing is I don't think most people appreciate it for what it is, anyone but a diesel guy probably figures the trucks running poorly.

 

[Slim Shady]

I guess I better get in on this. I wanted a turbo that would be a good match for the motor, and a good towing / working turbo, I was willing to give up a little zip off the line for a lot more usable rpm range.

The Original Mitsubishi turbo was not quite as spry off the line as the ATT, There were a couple of tweaks to get the acceptable compromise. The ATT is not GM X fast at spool up but it is also not a dog off the line either.

I thought about a big v8 motor with 6 or seven pounds of boost at 1200 rpm, in the old world we called that lugging a motor. The eights were not designed for that kind of stress, now add the fact the motor is not a stroker but an over square motor, power band is from 1600 to 2800, work it there and it may live a long time.

These were just some thoughts, no math just pure speculation / I believe the boost at lower rpms with the high compression ratios adds to block failure. Just my two cents worth,

As far as the exhaust issues, I have to give Buddy credit, he did work out the exhaust issue after his initial pm to me that the turbo only had 5 psi boost and smoked like a freight train when he installed it. We briefly touched on the exhaust and buddy replaced it without condemning the turbo. The problem with a lot of things is that there are variables between each of our trucks, most problems have a basis in the exhaust, or intake restriction. The ATT does require a free flowing exhaust to get the best benefit. One caveat I will note, I recently purchased a K47 air box and the large filter, made a little difference in boost response, and the engine seems to breath easier, up to 3400 rpm,

I do think that TD has a valid point, some forum members may not be as informed as others and may read spools slower and stop at that and dismiss the turbo. There loss I guess, the intent is not to hide anything, or not report anything that may be valuable in making the decision to purchase an ATT turbo. I always tell buyers or potential purchasers, ask the people that own one, not just me. If you are interested in purchasing a turbo or any product; a straight up vendor should never have an issue with a potential customer contacting a few owners of the product and get their opinion.

I like the fact that we are exploring territory, with different combinations of intake, exhausts and other components. It has been said here many times, the exhaust is the first upgrade that should be made. After that it is the owners choice, I ran an ATT with a stock program on my truck for about a year (no money for a chip), it ran fine, better than before, but boost stopped at 10 psi, fuel was maxed and the truck would stay there all day long. The chip really woke the truck up, then an optical bump, some timing tweaks and other minor tweaks.

I am humbled by the amount and scope of knowledge we have here at the truck stop. I know we can perfect things, there is always room for improvement .

 

[TMHark]

Now, hurry up and wait!!

Everything ordered and paid for ATT, KOJO ECM and FTB

Even got the fancy new custom fuel manager (can't wait to see what that's all about!)

So, it looks like I need to pull the top of intake off to do the IP side of FTB (and drill out that center piece), no way around it, right? I'll stop by NAPA and get the gasket so I have it handy

What's general turn around time on this stuff? Should I start pulling the inner fender pieces now and soaking everything in Blaster (doing a new x-over pipe also, and tapping it for EGT) or wait till it all gets here?

Thanks for all advice and encouragement!

 

[Detroit Dan]

I didn't pull my intake, I ran the hose up and around, carefully so it doesn't have any kinks. Maybe not the right way to do it, but it saved me a lot of time, and I didn't drop anything down in the intake either. Plus I can keep an eye on the new lines a lot easier. I was going to feed a wire thru then pull the line thru for a cleaner look, but I'm happy with how it turned out.
Turbo wasn't a bad job, I don't know but I'd say you should be able to get it all done in a weekend. Exhaust, downpipe studs are probably what could hang you up the most.

No matter how long it takes, I promise you will love your new truck!

 

[TMHark]

Project started!

Old turbo off (what a PITA)

Had to cutoff wheel the turbo mounting studs and nuts (they were all mush)
The inside front stud was a real treasure, thank goodness for a HD dremel to reach in there and chip away at it

ATT mounted!!
Only unforseen (minor) issue is that the mounting holes are too small in the oil drainback tube for the giant allen head screws, so I will take that back apart to ream them out.

I also have a some polished aluminum tubing and rubber connectors leftover from an intercooler project to replace that lovely orange hose ):h ):h

When I have manifold off, I'll get it bead blasted for a little show & shine (got a buddy who offered to do it for free) I'll take a pic when done

Dan - how did you do the IP end of FTB (drill out and change fittings) without removing the manifold?

C'mon KOJO and FTB, the hard part is done!!

Hey - if anyone wants my old turbo (AS-IS - has 200k, endplay, and needing mounting studs) FOR FREE, they can come and get it NO SHIPPING
If I can locate the new unused rebuild kit for it that would be $50, (cost $100 new)

 

[ocalasales]

Terry

I'm interested in the GM8, please pm me price shipped to 34482

Thanks

Bob

 

[JiFaire]

Good job, Terry - looking forward to some pics (and some pics of your nice intercooler install!)

 

[mamzerook]

Wow....