6.5TD Power

[More Power]

I received the following email earlier today from member Todd Falbo, who asked about power and the 6.5TD Project. I thought I'd reprint it here, in case anyone else had ever wondered the same thing.

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Hi:

I am experiencing problems with my 1994 Chevy 6.5 TD truck. The truck is still running fine but it is making a loud knocking sound that is very predominant from the engine compartment. I really haven't had time to look into it and pinpoint where the sound is originating; I'll do that this weekend. I would like to build (or have built) an engine to replace the one currently in the truck and I am very interested in your 6.5 TD project truck.

I am curious to know how your project truck does in the "Pull-Off's"? I didn't see a time on any of the 18:1 6.5TD trucks in your article "Evolution of power". You did publish numbers on Ken's truck but I do not know the particulars of that truck. What type of numbers does the project truck produce on the dyno?
In terms of RWHP and torque.

Thank You
Todd
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Hi Todd,

The Project truck has run the Pull-Off hill a total of four times. It produces 48 mph while running in third gear (direct). If we were to install a Peninsular non-wastegated turbo, and could run in 2nd gear, the top speed would be closer to 55. The GM-8 turbo is not free-flowing enough to allow full power above 3300 rpm without causing exhaust backpressure and EGT's to rise too high. We can use full power while running in direct, but we lose the torque multiplication advantage of 2nd gear.

A stock Duramax cannot increase speed while running this hill in direct with a 10K trailer. The Project 6.5 truck can sloooowly accelerate in direct. Best Pull-Off speeds with a stock Duramax come when using one gear below direct.

We've had the truck on the rollers one time. Unfortunately, BD's dyno tech tried running it like a Dodge Cummins, and limited wheel speed to 60 mph, which translated to about 2700 rpm in direct. The Dodge Cummins has historically produced its best horsepower at 2700 rpm. On the other hand, the 6.5L turbodiesel produces its best horsepower at 3600 (mechanically injected). However, even at 2700 rpm, it still produced 205 horsepower. A stock 6.5TD produces 140-160 hp at 3400-3600 - or about 100-110 horsepower at 2700.

The Project 6.5 now has nearly 130,000 miles on it without any sort of problem.

Hope this helps,

Jim

[Jim P]

My truck says on the valve cover that it has 190 hp. Do stock 6.5tds really only have 140-160 hp?

[rjschoolcraft]

At the rear wheels...

[richard7]

According to the GM power curve, The 6.5 TD ('98 up) is making 190 flywheel HP from 2500rpm to 3200 rpm. Than it goes up a little to 195 HP at 3400 rpm.

I think it is fair to say that the engine is making maximum horsepower from 2500 to 3400 rpm (redline). I should than translate to the 140-160 RWHP from 2500 to 3400 rpm.

[More Power]

http://www.thedieselpage.com/images/powergraph65.jpg

These are "flywheel" power & torque curves.

MP

[richard7]

Jim,
Those curves are for pre-1998 engines with a rating of 190 hp and 380 lb-ft.
The post 1998 engines are at 195 hp and 430 lb-ft, and have a different torque and power curves.

I would send a pic of it if I could (the image button is asking for a URL address???) but the curve I have is from the GM powertrain web site. The engine has been removed from the site since they removed the avalaibility of the engine for the 2003 Express/Savana vans.

Maximum torque is 430 lb-ft @ 1800 rpm

Power @ 1800 rpm is 147.4 hp. (430 lb-ft).
Power @ 2000 rpm is around 162 hp. (425 lb-ft)
Power @ 2500 rpm is around 190 hp. (400 lb-ft)
Power @ 3400 rpm is 195 hp. (285 lb-ft)

[More Power]

Here's another image that shows more 6.5 dyno data (both stock and with a few mods) obtained at the 2002 TDP Rendezvous in BC.

http://www.thedieselpage.com/images/bd06.jpg

Have a close look at John Presley's 1999 6.5 data and with what mods he's added.

MP

[Kennedy]

Not sure just why, but the (my) 6.5 just does not seem to score well on the dyno. I know that mine is at/near equal a stock Dmax, but for some reason it hassn't put up the numbers like it should. Once I have my own dyno, I should know more about how it does with air forced through the intercooler etc.

I should note for the Dmaxers out there, the CA truck (tpitt) did not do what they have listed. Terry should have the correct number, but the joke of the day was writing the CA emissions Dmax up as top of the stockers.

My numbers are correct, although no longer current... :D

[Jim P]

To you guys that have put your trucks on dynos. What do these rollers look like? We make some rollers at work and also rope drums for overhead cranes. Sometimes when we make a new one the old one scrapped after we get the dimensions off it. I could probably get a couple and make up my own set of dyno rollers. Our local antique tractor pulling club has a dyno that hooks to the pto on the tractors and could probably be hooked to the rollers to get a pretty accurate measurement of actual hp. Anybody have a picture of one of these roller setups?

[More Power]

Here's a pic of BD's new dyno setup.

http://www.thedieselpage.com/images/dynorollers.jpg

MP

[Jim P]

More Power,

Thanks for the picture.

I am really thinking about building one of these that is portable to take around to the tractor pulls and have people pay a small fee to see how much power their truck has.

Everybody always thinks that there truck is stronger but this would tell the real story.

I can't really tell from the picture but are the rolls covered with rubber or are they just smooth steel? I was kind of concerned that a truck with alot of power would spin on the smooth rolls. Also do they check the hp with the truck in high gear or do they use direct?

[ 10-02-2003, 03:19 PM: Message edited by: Jim P ]