Dynojet questions

[1BIG44]

Today a group of us got together at a local Dyno shop. With a DynoJet. They had done one guys truck previously, but this time couldn't figure out where to get a signal from. For future reference could you tell me where to pick it up.



Also, the numbers on the turned up trucks seemed to be way low, yet the stock trucks came it where expected. Doesn't the dyno have to be "loaded up" . The tech says just the weight of the drums, but I always thought that a load was placed on them. No one could build decent amount of boost. I am guessing that there was not enough resistance to reach the true potential of some of these trucks, could this be the case? I am really ignorant on this subject, and could use a little help here.



Thanks,



Wes

 

[joesoot]

My question is, is it possible to simulate a road load on a Dynojet?

If not, it seems as though running on a Dynojet dyno isn't much better than revving in neutral to get someplace.







I just noticed this surfing Dynojet's site-

I didn't know DD and Dynojet were directly related outfits:

http://www.dynojet.com/compinfo.shtml

 

[C Schomer]

I know the feeling! I took mine to Cummins RM last summer for my E test and asked them to do peak HP and Tq while they were at it. I had to leave the truck and didn't get to watch. Besides that, their emission tester broke and I didn't get my sticker! The tq was 2430 @ 2k rpm and hp was 236 @ 2500 rpm. If I divide the tq by the axle ratio(3. 54)I get 686, which I figured is in the ballpark but 236 hp sounded low to me for that much tq. A friends HO did 207hp on the same dyno. I asked if the operator stepped on it hard enough to get the egt to around 1300 when he got the hp reading but nobody knew how he did it. I think dyno numbers are only as good as the operator! On the other hand, I used to share shop space with another OTR truck owner that built a HOT NTC 350. He balanced the engine, put in higher(instead of lower) compression pistons, a giant turbo and turned the fuel and rpm sky high. He could gross 80K lbs and run 110 mph. He just dynoed it on the same dyno and got 590 hp. . 236 is exactly 40% of his hp, so I don't feel so bad! Craig

 

[Joseph Donnelly]

Diesel Dynamics and Dynojet are separate companies. Lawrence did work for Dynojet in the past and maintains a good working relationship with them. The principle of the Dynojet is inertia and the drum can be built with different amounts of inertia, expressed in slugs. Some Dynojets have more slugs and are thus able to load our Turbo Diesels more. Lawrence has begun to market a custom line of Dynojets with high slug values specifically for testing turbocharged engines. That is kind of a joint venture in that Dynojet will build the dynos to his specs for him to sell. As far as I know, that is the relationship you might be hearing about.

 

[CRuD]

who knows

Wes

The New Egland folks are doing a Dyno on the 15 of Dec. I am thinking about running up there. My truck turned out higher numbers than I thought, 220 Hp is great I thought I would be pushing 200 once you figure in all you lose going through the Trans, Dif and then the tires.



See Ya

Chris

 

[1BIG44]

Chris those were nice numbers. I knew you would be close to that.



Dec. 15th it is a long ride, but hey if you are game I'm with you.

David might want to tag along too.



Wes

 

[joesoot]

Originally posted by Joseph Donnelly

As far as I know, that is the relationship you might be hearing about.

The relationship expressed on the link I posted listed "Diesel Dynamics Dodge Cummins Performance Kits" as a Dynojet product along with HYPERPRO Suspension, Carb recalibration kits and fuel injection enhancement systems. Makes no difference to me as either way DD is truly a class act.

Does DD use a custom drum to load the vehicle for boost?

This could explain some variations (read:low) folks see when taking their TDs to a gasser or NA oriented dyno shop.

?

 

[CUMINNTSTRKN]

joe



my truck has spent alot of time on both dynojet and mustang dyno's. the hp is close between the two. but the trq is always better on the mustang due to the loading. imo the dynojet is more repeatable.



jim

 

[BIG BOB]

Cuminntstrkn,



Do you mean repeatable or replicable?



I know you have done alot of runs on dynos, just wanted your opinion on which dyno you feel is more accurate or gives us a better insite on the performance of our Cummins.

 

[CUMINNTSTRKN]

bob





the dyno jet has no inputs that the guy has to enter. there are no load cells that get hot. so imo the dyno jet is idiot proof. you bolt in on and hit start. i use the same dyno-jet alot and it's always within 1hp. we don't get the trq from dyno-jet that we get from the mustang but the hp seems close. mustangs don't use a correction factor so the test at bd was a good one since it was at sea level.



for those of you that think the turbo motors arn't affected by elevation are smoking crack.



i just dyno'd my truck on a mustang dyno at 6200'. with nos it made 425hp at bd i made 564hp the only difference was the elevation. i had a little slipping at 6200'.



without nos i made 356 at 6200' and 443 at bd. so i would say that 100hp is modest at 6200'



jim

 

[Todd T]

to answer your ?

1Big44, there is a wire on the 01 trucks that will give you a pickup. it however drops off on ETH's at around 2000RPM's. the wire is a red with green trace located in the wire loom above the valve cover. with that said, I would recommend your shop purchase a magnetic pickup that can be used off of the Crank. as the wire in question is NOT a verified Tach signal. but will do in a pinch

 

[MikeR]

Craig,



Your torque estimate is alittle off. If you cannot get a torque reading on a dyno, then there is a formula you can use to find it. This formula has been covered in a past TDR issue and a few times on this website.



(hp) x 5252 = X

X divided by (RPM) = your torque figure



so... .

236 x 5252 = 1239472

1239472 divided by 2500 = 496



236hp and 496tq.

 

[1BIG44]

Thank you very much Todd. That is what I needed to know.



Still searching for the other half of my question. Can you place a load with the dynojet. Previously when I dynoed on a dynojet I was able to hit max. boost (at a different shop). But on Sat. no one could build any boost to speak off. An extremely tuned 12 valve that can easily hit 50 lbs, was only seeing around 35, and another could only make 15 lbs, whereas he can hit alot higher on the street. THe only stock truck to pull showed numbers slightly higher than I expected, yet the bombed trucks were just barely above him.



What good is that big brake for or is the only resistance the weight of the drums.



Sorry for my ignorance, but this is confusing the #@** out of me.



Wes

 

[C Schomer]

Mike R, I didn't get a thorough printout - it only showed 2700 as the highest rpm tested and 1900 was the lowest. It said peak hp was at 2500 and peak tq was at 2000 - it didn't give hp AND tq together at each speed. I guess that's what I get for free! Don't dynoes really only measure one parameter(hp or tq)and calculate the other? I'm going to our local dyno meet Sat and I don't want to be the first one on the dyno. I want to watch a few and see if it appears to be accurate and done correctly. Craig

 

[CRuD]

Wes

I don't think we will find out the info you are looking for. All the more reasons to run my truck on the Dyno again. If I add the EZ will that shoot me to the 285 mark?? 220(dyno) + 65 (EZ)= 285Hp.

I'm not being a smart @$$ all I want to know is the Hp and Tq of my truck.



Thanks Wes

See Ya

Chris

 

[1BIG44]

The advertised gain with the EZ is not necessariyly at the peak, some claim that the gain is in the lower rpm's. But I would expect you to see a gain of about 50 rwhp. I wouldn't think you would be at 270, because like you said the 220 is suspect. Probably would be the strongest stock ETH on TDR. I always figured around 200 hp stock. But I don't have a lot of data to support any of my opinions.



Wes

 

[joesoot]

Didn't Jim (CUMINNTSTRKN) dyno around 250hp stock?

Wasn't Evan A. Beck in the 23X range?

Who else dynoed an ETH over 230rwhp stock?

I don't think 220 is suspect.

 

[CUMINNTSTRKN]

if you look at this graph you will see i only gained 32hp peak but over 60hp at 2000rpm.



http://community.webshots.com/photo/9147502/9889601ViWxfqONiw



jim

 

[MikeR]

joesoot,



I watched Evan Beck's ETH dyno 237hp stock, and I also watched Vaughn MacKenzie's ETH dyno exactly 245hp stock. I saw another ETH lay out 227 stock, but can't remember who's is was.



-Mike