Engine/Transmission (1998.5 - 2002) Comp performance differences, ETC/ETH?

[Gary - K7GLD]

While I am quite happy with the performance increase after adding the Edge Comp on my otherwise stock ETH/DEE, I have subsequently learned that the power increase when applied to the ETH is CONSIDERABLY *less* than what is commomly obtained with the ETC... Naturally, Edge didn't see fit to mention that fact in the nice dyno and info page they have for their products...



SO, the natural question, is WHY, when the ETH starts out with more power than the ETC, WHY does the Comp provide so proportionately LESS peak power/torque for the ETH, to the extent that the Comp-equipped ETC vastly SURPASSES the similarly equipped ETH?



I mean, the Comp equipped ETC - according to Edge's web page - is good for about 800 ft lbs torque, vs about 675 I've seen listed for ETH owners - that's a BIG difference! Max Hp advantage for the ETC is similar...



Is it injectors? Injector pump? Camshaft? All 3? I mean, even after a significant head start in stock power, the ETH seems to improve by only another 50% or so with the Comp, compared to a similarly equipped ETC - that just doesn't seem right!



Is there any SINGLE mod that can be done to make things more equitable - and still maintain reasonable fuel efficiency? I sorta suspect some will say the ETH needs bigger injectors (among other things... ), but I *also* suspect the existing injectors were used for a REASON - perhaps economy at the intended power level - without much room for additional power gains?



Not sure I would wanna go to great expense and trouble for additional power - but sure would like to understand what's going on a bit better - and WITHOUT the 24 vs 12 valve digs - I still feel one engine is DIFFERENT than the other, but not necessarily "better"...

 

[JR2]

Gary - I think it has to do with the version of VP44 the ETH uses. If I remember correctly it is smaller than the ETC.



What you see happens with the EZ also, maybe the timing on the EHT is already advanced so there is less room to make more power??





JR2

 

[Whitmore]

JR2 is correct

it is also from the injectors, the eth has smaller injectors than the etc, I think Dodge did this because it was too powerful, I installed 275 injectors and it made a good difference, I did that before the comp

 

[KatDiesel]

Several reasons... .....



The ETH is a different animal..... different compression, different injectors, different VP44.



If you wanna equalize things..... you gain 70hp using DD's VP44 on an ETH vs only gaining 40hp with DD's VP44 on an ETC. That would be one way... but exspensive consider the cost of pumps just doubled nearly. Thats about all you can do to "level" the playing field. I don't know of any way to completely level the field... . never really worried bout it since I have an ETC. All my ETH "experiences" come from Floor It's ETH...



You add injectors... . you still won't "catch up" to a similar equipped ETC. ETH's seem to benifit more to injector changes then the ETC's do . . on the lower end of the scale.



Thats why on the ETH's. . many people stick with injectors and a "minor" fueling box.

 

[Gary - K7GLD]

WELL, like I said, I'm pretty happy with the power increase I *did* get - I've ended up with what I consider a pretty well-balanced tow rig for our 7,000 lb load... I get 32 psi boost - never more than 1200 EGT regardless of how long or steep the grade, and economy seems well within expectations, and no hint so far of clutch problems or overheating... It's mostly a simple matter of curiosity as to why the apparent BIG difference in engine reactions to the same box... As well as curiosity as to whether there might be some quick and dirty "magic cure"...



But there never IS, is there!