215 Hp GM program myth or actually exists

[Turbine Doc]

This post http://www.dieseltowingresource.com/showthread.php?t=5216&page=3 got me to wondering again, been long time since I had pondered it or sought the answer. Evidently I had a 99 PCM with higher than stock F 63^3 mm fueling was it a unmarked tweaked PCM, or the oft rumored 99+ yr 215 Hp program. When I did look into it I was told & don't remember where that it never made it to mass production but some RVs and big trucks 4500 & up may have gotten it.

So can any of you 99+ guys/gals have a look on a scanner to see what your WOT max fuel rate is so we can put the rumor to rest with data, vs supposition.

 

[1999gmc]

On my Snap-on scanner I was getting over 74 mm3 everytime I would hit WOT. That was why I was so hesitant to spend $500 on a reflash. I am going to find out in 3 days whether it was worth it or not.

 

[1999gmc]

I got a core to send Heath, So I still have my factory computer.

 

[JiFaire]

I'm really interested in this... I never knew that the HO tune really existed (from GM)... I thought that was just one of those things that never got off the drawing board.

Keep us posted!

 

[qwomack]

I had a post about this same thing back in November 2006 over on the place. I was seeing 74 mm3 at WOT and questioned whether or not I had an unmarked reflashed PCM. Mine is a 98 model however and not the fabled "99" model. I too also still have my original PCM. In the "for what it's worth department", I noticed a significant difference when I went with the Heath Max-E-Tork.

 

[DennisG01]

Well, I think I can sort-of verify this. A few years ago I had an early JK tune (Wester's), which at the time was on par with or slightly better than the older Heath tune (based on a hill-pull that I do to compare things). Anyways, the truck went into the dealer - I told them I had a tune and not to re-program, but that vital instruction somehow got overlooked. When I got the truck back, I noticed something was different because my boost was back to stock levels. I figured I might as well test this out. Power wise it was close, but not equal, to the JK tune. But in going up the hill, I had to back off because the EGT's were getting high way too fast. Based on the numbers I recorded it was faster than the original stock ECM and the EGT's climbed at about the same rate. I'll see if I can dig up the stats from that run.

By the way, Kennedy was gracious enough to re-tune my ECM for free!

 

[Turbine Doc]

look like it made it to more than a few PCMs, one I ran was/is not on par with current offerings from Heath/Kennedy/Westers/SSD, so if not able to afford a tune, and you have a post 96 truck to 99, go junkyarding for the 99 & up PCM, if you are an S PCM'd truck any 96+ F will be a plus for you from 56mm to 63+ or higher it would seem if you get a 99+ year PCM.

Keep reporting in you 99+ folks info is how we learn around here.

 

[Rodd]

On my Snap-on scanner I was getting over 74 mm3 everytime I would hit WOT. That was why I was so hesitant to spend $500 on a reflash. I am going to find out in 3 days whether it was worth it or not.

This could explain why you were able to tow much better once you went w/ the marine injectors. Didn't you say you notice a difference towing in the mountains keeping up w/ your friends dodge? All that you have is a boost fooler, I/C, and marine injectors right?

 

[Rodd]

I seem to recall the last time I went to Utah I got close to 80 mm3 when climbing some of those passes at 85 mph. I may be mistaken. I'll see tomorrow when I go back for "hell week" Hopefully my mother in law wont force us to leave early if you know what I mean.

 

[gmctd]

The HO tune would not have been for the emissions-compliant 1500 "S" series trucks in any scenario - any slight increase in power will result in higher exhaust back-pressure which will blow the EGR valve open at higher mechanically-forced Boost levels - around '98-'99 power was increased from 185hp to 190hp for L56 "S" and 190hp to 195hp for the L65 "F" series - 215hp was a proposed but never executed L65 "F" upgrade, due to no charge-air cooler and the GM-8 - that observed fuel rate is what the PCM is calling for, and likely does not reflect the actual delivered fuel rate (even more unreliable with a SnapOn scantool; Tech2 and Autoenginuity are very accurate in display interpretation\interpolation) - those that have switched from "S" to "F" PCM will see increased fuel-rate demand - those that have increased TDCO will see increased fuel-rate demand - that's part of the increased power seen after tweaking the timing - put your unmodified "S" PCM back in, reset timing to oem 0.5*TDCO and check out your "new-found power" - those that participate, reference your applied scantool of choice, TDCO timing, and don't forget to include any info on any forgotten hyperchip upgrade, as those were simple fuel-rate increases with no thought for EGT, Boost, Timing, etc.

 

[Missy Good Wench]

This very interesting.

The Heath Chip I have in my 95 dually is "supposed" to be capable of delivering 90 mm3
at WOT
I have never had the rig on a scanner to see but judging by the way it runs and the boost and egt I would say it entirely possible.

My 94 Burb has one of those early chips that was extremely doggy. 5068 IP to add more issue.

I have also heard of the 215 HP tune but dismissed it as wishful thinking.

With a wide open 3-1/2" or larger exhaust and a cat MIA the extra fuel will certainly do no harm in the HP dept.

best

MGW

 

[Monarkman]

Most if not all of these later trucks state horsepower at a given fuel rate. My 1998 says 195 at 64mm3 and I'm sure 1999gmc can confirm his truck says the same. If there is a midrange fuel bulge up to around 76mm3 and then the computer pulls back fuel to around 64mm3 like Kennedy said, then maybe the this later flash had a little more midrange oomph but still made just 195hp.

 

[1999gmc]

This could explain why you were able to tow much better once you went w/ the marine injectors. Didn't you say you notice a difference towing in the mountains keeping up w/ your friends dodge? All that you have is a boost fooler, I/C, and marine injectors right?

Yeah. And exhaust. Yes, mine has 195 at 64mm3.

 

[steelydan]

I have been thinking that my 1999 Sub has a "hotter" than stock tune. It has a 4" exhaust and no cat. On Saturday I ran up the Coquihalla to Kamloops. The highway had about 6 inches of snow on a 11% or so grade. I was in 4x4 with 11lbs of boost and egt's hitting 1200 Pre turbo. I had to back off the throttle. Truck just seems to get to the higher egt's easier than the previous ones I have owned. I do not have a scanner.

 

[DennisG01]

I have been thinking that my 1999 Sub has a "hotter" than stock tune. It has a 4" exhaust and no cat. On Saturday I ran up the Coquihalla to Kamloops. The highway had about 6 inches of snow on a 11% or so grade. I was in 4x4 with 11lbs of boost and egt's hitting 1200 Pre turbo. I had to back off the throttle. Truck just seems to get to the higher egt's easier than the previous ones I have owned. I do not have a scanner.

If you're getting 11lbs of sustained boost (not spikes) then you most likely do have a tune (unless you're boost gauge is not correct, and that is very unlikely). Although 11% is quite steep (and of course the snow makes it work harder, too), I wonder how efficient it is since you're hitting 1200* with nothing in tow. What speed/gear were you in at that 11lbs? A good tune should give you more power while keeping the EGT's lower.

 

[Goldsburg]

This post http://www.dieseltowingresource.com/showthread.php?t=5216&page=3 got me to wondering again, been long time since I had pondered it or sought the answer. Evidently I had a 99 PCM with higher than stock F 63^3 mm fueling was it a unmarked tweaked PCM, or the oft rumored 99+ yr 215 Hp program. When I did look into it I was told & don't remember where that it never made it to mass production but some RVs and big trucks 4500 & up may have gotten it.

So can any of you 99+ guys/gals have a look on a scanner to see what your WOT max fuel rate is so we can put the rumor to rest with data, vs supposition.

TD -

I have seen the 215HP calibration on a Workhorse / GM Prototype coach, as I used to work for Workhorse as a Test Engineer. This happened one day while I was assisting one of Proto Build Technicians with some diagnostics (since I was the resident diesel-head).

We took this thing out for a drive once the lift pump, OPS, and relay were replaced. HOLY SH!T... that thing was cranking out 13PSI of boost sustained with a vacuum system in place via the Tech 2. I don't recall the fuel rate, as I was too enamoured with the boost pressure, but that 18,000lbs would really scoot! So, what does this mean? It means that this calibration DID exist and was probably implemented on L65 engines in RV applications as TD said. Now that I know what that calbration is/was, I wish that I could get my hands on the coach again. That ECU would be sent to Heath for replication onto others ECU's...

Regards,

 

[gmctd]

As with any responsible oem mfr, any proposed upgrade is always field-tested several years B4 actual release of product - meaning, at least 50 prototypes are released to select execs and dealers across the country for thrashing - official reports from the victims vis-a-vis those test mules are then used to determine releasability feasability - those mules, usually rode hard and put up wet, eventually fall into the wrong hands, and thus can be found where-is as-is in the used vehicle pool - that includes the Wankel quad-rotor mid-engined 'Vettes, the Chrysler turbine cars, even the prototype Wankel-engined Chevy Vega - they all still show up on the block every so often, available to the highest bidder - the largest platform for the 6.5 was the Lo-Pro 3500, a ton-and-a-half look-alike, and the motor home chassis, usually in pusher config - if you can find a 6.5TD 215hp version, whatever the platform, nab it for posteriority's sake - that would include the all-important documentation scheme, which will put paid to that tale....................

 

[steelydan]

If you're getting 11lbs of sustained boost (not spikes) then you most likely do have a tune (unless you're boost gauge is not correct, and that is very unlikely). Although 11% is quite steep (and of course the snow makes it work harder, too), I wonder how efficient it is since you're hitting 1200* with nothing in tow. What speed/gear were you in at that 11lbs? A good tune should give you more power while keeping the EGT's lower.

90kmh 3rd gear...stayed at 11psi for over 1 minute till EGT's got to 1200. Boost gauge should be correct as truck has about 3 psi on the flat freeway at 110kmh. I had about 600lbs of rigging tools in the truck. I have seen 11psi before when towing for over a minute, but again EGT's get too high and I back off throttle.

 

[DennisG01]

90kmh 3rd gear...stayed at 11psi for over 1 minute till EGT's got to 1200. Boost gauge should be correct as truck has about 3 psi on the flat freeway at 110kmh. I had about 600lbs of rigging tools in the truck. I have seen 11psi before when towing for over a minute, but again EGT's get too high and I back off throttle.

I agree - it sounds like your boost gauge is OK. Aside, from a re-flash, you could also have a "boost fooler". If so, you can turn it down. Typically, you'll find this "extra thing" connected in-line at the boost solenoid. Kennedy sells them (I used to have one, but never experienced those EGT's w/nothing in tow - and mine was to about 12/13 psi), some people make them. You can see a picture of one on Kennedy's site - look for "TD-Max Boost Controller". My guess (and it's just a guess) is you either have a boost fooler with stock programming, or an inefficient re-flash. But, then I've never driven up a 11% grade in 4WD in the snow at highway speeds, either!

 

[Monarkman]

Just imagine if the tune Goldsberg describes had made it into production around 1996. This program coupled with a factory intercooler would have made the 6.5 a real contender in the diesel towing market at that time.