Gas Vs Diesal... wierd question

Matt_ · April 15, 2005

Ok so here's the question. you have two vehicles with similar sized engines, ie both 6.0, 5.4, etc.. only difference is 1 is a diesal and the other is a gas engine.

Hell, say you have a 6.0 L gas engine in a chevy 1500 and a 6.6 diesal in the same 1500--- both engines with auto trannies, both engines standing still at idle. which truck will spin tires easier when you slam the gas?

and i know it depends on tire size.. so figure stock tires.. but then answer the same question for in increasing tires size: ie, what will happen with 32's, 33's, 35's, 36's, 38's.

he seems to think that a diesal engine cant spin any tires... but he's basing his opinion on equations from our thermodynamics class and the fact that he drives a late 80's merceded that's diesal (and slow as hell).

PeterbiltChrome · April 15, 2005

both engines in your example don't go into a 1500...(except denali and SS get the HO 6.0 gasser) and what's the point of this anyways?

A turbo diesel will have to spool up the turbo to create more hp and that is probably the only difference between the diesel and the gasser.

If you drag race (and intend to do well on a run) there is no desire to spin the tires when you smash the gas out the gate. Diesels have more weight on the front end, less in proportion than the back. It isn't hard to break em loose. Auto transmissions are slush-boxes that vary power input/output and are slow in reacting to smashing the gas. Tire size and gearing of course are factors.

Your buddy doesn't think diesels spin tires? Maybe your buddy is slow as hell~

Matt_ · April 16, 2005

Im not talking about drag racing and getting good 1/4 times or anything. This discussion came about because in our mechanics class we have an equation directly relating horsepower to rpms. Then we started combining some thermodynamic equations that have to do with efficiencies and other crap- and basically , just from the equations and theories he doesnt think that a diesal can spin tires. And yes, the laws and equations all comply except he's mis-interpreting it all.

basically he said that in order to spin tires you need a quick "snap" of torque to change from static to kinetic friction between the tires and the road.. i say yes thats true, then he says that the diesal engine takes more time and works at lower rpms and blah blah blah- and i told him that is also true, however the time isnt a few seconds, its maybe 1 thousanths longer than a gas engine.

ok i can write like a 3000 word essay of all the reasons why i told him i was wrong. basically i want someone on here to back me up:

**** My stance, not only can a diesal engine smoke tires- but if you increase the tire sizes a diesal engine will be able to still break them loose while a gasoline engine wont be able to. (up to a certain point of course)

He's basing his ideas on equations and the fact that he drives a slow a-- 89 or something mercedes. im basing my ideas on the same equations (however with a better understanding of the concepts obviously) as well as the fact that ive driven many new diesal trucks.. and the fact that my buddy has a dodge cummins on 39s and can smoke em.

I just want him to read some others opinions on the subject

Matt_ · April 16, 2005

oh, and i know both engines dont come in that truck. but if i said two different trucks then someone would obviously say "well they're two different size engines with different displacements on different vehicles with different transmissions with different gears with different GVW's"

know what i mean

im talking about theoretically- two trucks with the same tires/gvw/gearing/and the most similar sized engines but gas vs diesal.

like dont go comparing the 1.4L turbo diesal in the old Rangers to the 6.0 gas engine in the chevy's.

snoman · April 16, 2005

Auto transmissions are slush-boxes that vary power input/output and are slow in reacting to smashing the gas.

<{POST_SNAPBACK}>

Maybe you cars but I have a few that will jerk you into the seat the instant you crack the peddle. There is nothing slushy about a good hydromatc. The only thing slushy is some of the computer controled engine hooked to them and some of which have mushy off idle responce. I have a old J20 P/U with a AMC 360 that if you jump on it you will hear the tires start to break loose on pavement the instant you jump on it from a idle with no power braking and it is 26 years old now!!! You have to drive it with a very light foot to keep it from jumping everytime you start out. It is a fun old truck to drive with a very strong motor though it sees little use these days.

rascal · April 18, 2005

diesel make more torque, but wouldn't think you could "stick" diesel in one spot, but a moving burnout should be very possible. brake torquing you could all day long in diesel, well till something breaks or the tires blow.

snoman · April 18, 2005

diesel make more torque, but wouldn't think you could "stick" diesel in one spot, but a moving burnout should be very possible. brake torquing you could all day long in diesel, well till something breaks or the tires blow.

<{POST_SNAPBACK}>

They may make more torque after boost build but only for a limited RPM range and they are all dead or near it torque wise by 3000 RPM where a gas engine justs starts to strut its stuff. and 400 ftlbs of torque or more at 4000 RPM will do more "damage" than 650 lbs at 2000 RPM and a gas engine can make power over a 3000 or 4000 RPM range unlike a diesels 1000 RPM range give or take. On burnouts, you have to power brake a oil burner to build boost but with a big gas engine you can just get into it and as far as burning the tiires off of the rim you would probaly burn the tranny out in a diesel before a gas truck because it has to use taller gears and to work which increase driveline strain vs a gas engine with deeper gears. To me power is when you just step into it and they burn, not when you have to take a few seconds to power brake and build boost.

rascal · April 20, 2005

ya of course it would be alot harder on the drive train, and you would have to be in a higher gear to keep the rpm range right. you know I'm thinking manual shifts, not sure you could get an auto to get the gears right.

I know you can do and brake torque with an auto. I seen a buddies, /cough, power stroke do one a few years ago. But I'm not sure given the rpm power range how'd it do with out cheating with the brake.

Turbine Doc · May 9, 2005

Oh, contraire fellow diesel enthusiasts the GM 1500 series most definately can have a Diesel in it not a D Max but a 6.5TD last offered in 2000, a properly tuned 6.5L TD will make the most ardent neighsayer take notice. My 6.5 will outshoot many stock Diesel and gas trucks and spins the tires quite easily. all bets off when going up against a peaked Diesel other than 6.2/6.5. Different engine design puts limits I can't overcome without putting engine at risk.

Chris97K1500 · May 12, 2005

http://www.truckstv.com/show_details.aspx?iid=4501 Here's a link with a DuraMax doing a burnout, just to show it can be done. There's one of a Dodge doing the same thing on the site there. Chris

ZE5 · April 22, 2006

I dont know if someone mentioned this earlier... so sorry if i'm reapeating this right now, but the fastest truck in the world right now is a Banks power Cummins powered Dakota.

Check out Trucks TV on sunday mornings on spike, every so often they'll replay their power buildups on the DMAX, Powerstroke, and cummins diesels. Tracy does some of the coolest burnouts in those trucks.

cowboybinkz71 · May 2, 2006

Your diesel would spin tires more easily and here's why. First the diesel is much heavier which shifts the weight balance further forward making it more likely the rear wheels will break loose. Secondly, a diesel engine produces way more torque (which is what really gets teh vehicle moving...h.p. is nothing but a product of torque) at a given RPM. Some of the members here are thinking of a conventional turbocharger with fixed vanes, such as the turbos on teh early D'max (01 thru 04), the Cummins trucks, and teh 7.3L Powerstrokes. BTW, before we go any further, I've owned one of each of the previously mentioned diesels and turned them all up. With a conventional turbo, you will have some turbo lag, which varies depending on outlet size and such. Anayway, with the turbos offered on the newer Maxi Pads and Powerstrokes, you have no lag at all and your torque comes on early and stays there. So, if you take both these into account and the vehichles are identical, the diesel would be more apt to experience wheel spin IMO.

Back in '02 and '03 when I had an '01 Dmax with the Edge Juice I could hang with Z28 Camaros and Mustang GTs didn't stand a chance. WIth that truck, I could power brake to build boost and if I didn't launch in 4high I"d roast the tires in 1st adn 2nd and in 3rd I'd finally start forward momentum thanks to the Allison slushbox. I sold it for a '00 Cummins 3500 4x4 that could drag teh axles out from under my cattle trailer thanks to exhaust, small box, and a good torque curve. My most recent oilburner was a '01 Stroke wiht teh 6-speed and it was a great combination of the 2 with 4" exhaust, intake, and Edge Programmer.

With a diesel, you want an auto if you're going to race so you don't lose boost, and you want a bolt aciton if you're going to tow.

snownyet · June 3, 2006

650 ft lbs at 1600 rpm for a 6.6l diesel and 360 ft lbs at 4000 rpm for a 6.0l gasser... which one do YOU think will spin the tires easier? My D/A crew cab is sideways with a stab of the pedal on stock tires. My wife almost slapped the crap outta me for doing it yesterday to her surprise. This is my first diesel and Ill likely never own another gasser after driving it.

snoman · June 3, 2006

650 ft lbs at 1600 rpm for a 6.6l diesel and 360 ft lbs at 4000 rpm for a 6.0l gasser... which one do YOU think will spin the tires easier? My D/A crew cab is sideways with a stab of the pedal on stock tires. My wife almost slapped the crap outta me for doing it yesterday to her surprise. This is my first diesel and Ill likely never own another gasser after driving it.

<{POST_SNAPBACK}>

This depends a lot on the axle ratio behind the gas engine. Yesterday I drove a new 360 HP Dmax CC and another with a 8.1 and a 4.10 axle and the 8.1 was far quicker and more fun to drive. Because of the limited RPM range of a diesel, it has to up shift a lot sooner in a "burn out" and it looses its torque advantage. If you nailed the 8.1 is would go sideways instantly and the speedo would hit 60 or 70 standing still and it would light them for a very long time. You needed to torque up a Dmax and then as you started to move it would upshift and grab because torque was lost to gears. The BIGGEST mistaake that people make when they compare gas to diesel is axle ratios, A gas engine has a different power curve and needs deeper gear to make its power and BTW, a 6.0 can do a very impressive burnout because once you get them broke loose you can tack engine above 5000 RPM in first and really light them up while the diesel needs to upshift and the torque edge is gone. It is oall in the gears. If you had a 6.0 with a allision (you can order one that way) and installed some 4.56 gears it would surprize you what it would pull effectively and with the double OD it would still cruise at a lower RPM than a 6.0 with a 4L80 and 4.10. It may use a little more fuel (which costs less too) but it will also cost 5K less and it will pull very well too. GM used to offer 4.56's from factory on OBS trucks (ECM still supports it too) until they came out with 2500HD in 2001 and then they quit to give the Dmax a better performance edge because as stated above even a 6.0 with a 4.56 would do well and a 8.1 with a 4.56 would outpull a stock dmax and with double OD it would still cruse at about 2300 RPM at 70. It would use more fuel for sure (which is cheaper) but it would be a real towing beast.