Team Integra Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
966 Posts
Discussion Starter #1
Okay, in reviewing the dyno charts I'm a bit confused. There doesn't seem to be a whole heck of a lot of consistency, even in the cars that are only slightly modified (and as such should, presumably, be close to stock). Some have flat (theroretically ideal, I believe) torque curves and a resulting hp curve that is very linear. Others have continuously rising torque curves--even ones whose modifications don't appear to be drastically different from stock.

Now, correct me if I'm wrong, but Honda engines are supposed to be well designed for flat torque curves and linear power delivery. Yet, this doesn't always seem to be the case. In the FI setups, this makes sense. But in the basic NA ones... I'm a little confused.

Maybe I'm just being stupid...
 

·
Registered
Joined
·
31,217 Posts
it confirms that each engine breathes slightly differently no matter how similar the parts or the fact that it's the same model and it confirms how much tuning can make a difference. it shows how useless copying people's settings on VAFC's or SFC's are. flat torque curves don't just happen...they are a function of spending some time and doing a lot of work first intelligently planning your package to get what you want and using a wideband O2 sensor tuning her at the dyno or track.
 

·
Registered
Joined
·
966 Posts
Discussion Starter #3
Could the dynos themselves be a culprit in the diverse readings?

I'm also shocked to see such a wide variation based on the "quirks" of each engine--it seems very... strange. I don't know, I'm not much of an automotive engineer so I don't have enough knowledge to really say what an acceptable/typical "deviation from the norm" is (assuming the norm is a flat torque curve, with a noticable VTEC engagement in GSRs/ITRs @ 5600 RPM, and the corresponding hp curve).

It'd be nice if manufacturers had official (realistic) hp/torque curves for their products besides just peak numbers for hp and torque. At least that way you'd have an official baseline to work from; a sort of "control" in the tuning "experiment."
 

·
Super Moderator
Joined
·
25,239 Posts
(assuming the norm is a flat torque curve, with a noticable VTEC engagement in GSRs/ITRs @ 5600 RPM, and the corresponding hp curve).

GSR VTEC engagement - 4400 RPM
TypeR VTEC engagement - 5700 RPM
 

·
Registered
Joined
·
31,217 Posts
Justin, I would not base the torque curve on where the vtec was set at.

if they dyno using the same models, the variation is not that big especially if you use SAE corrected hp. If you compare between companies however, Mustang dynos must use a lower inertia drum or something since their readings tend to be 3-5 whp higher than the Dynojets. Dynopack dynos are the most accurate since they do not use drums and connect directly to the wheels. The tire/wheel overall diameter and tire bounce from having too much tire pressure plays no factor in the Dynapack reading. If you want to make it look like you gained big hp without doing anything, do a baseline run at a Dynojet facility and then add a set of rim/tire combinations that is smaller than stock and go to a Mustang dyno...
 

·
Super Moderator
Joined
·
25,239 Posts
No no MD, I was just letting him know the stock engagement of VTEC. He said it was 5600, perhaps I misunderstood him.
 

·
Registered
Joined
·
966 Posts
Discussion Starter #7
Justin Klemgold on Aug/22/02 said:
GSR VTEC engagement - 4400 RPM
TypeR VTEC engagement - 5700 RPM
Oh. Oops.


I knew that the number I picked wasn't quite right...
 

·
Registered
Joined
·
8,097 Posts
It really shows how important an engine package is. If you look at my dyno the torque curve is a little wild. But there are all reasons for why it behaves the way it does, it's the package that counts. If you don't put your parts together right you'll shoot yourself in the foot (like I did).
 

·
Registered
Joined
·
966 Posts
Discussion Starter #9
So far Gvtec seems to have one of the better dynos and since I'm getting a JRSC for my (future) GS-R his advice in particular has been most helpful...

The strange dynos are the ones (and I won't name them) that take serious dives for 500+ RPM. I'm wondering what that feels like to drive...
 
1 - 9 of 9 Posts
Top