My car is on the same setup on both runs. One was on a dynojet and the other on a dynocom. The first tune/graph was done using Crome, boost set at around 18psi but creeps past 19 by the end of the run. Second tune/graph was done on eCtune at around 17.5psi and falling a little by red line. I think this is tune related. Vtec was set at around 5200rpms on dyno 1 and 4200rpms on dyno 2. How do I get the flat trq curve that I want? My car seems to run out of breath shortly after 7400rpms. Peak hp was at 7200rpms on the second graph. Please give me some suggestions to give my tuner on how to achieve my desired power band. Thanks

Dyno 1: Crome, 18+psi, vtec 5200rpms. Nice flat trq curve. Looks like it could continue to make power to 8k.




Dyno 2: eCtune, 17.5psi, vtec 4100rpms. We set vtec to 5200rpms like it originally was and the car wasnt making much power. The blue graph shows vtec when it was set higher.

 

which tune feels faster?

 

I know the car is is "faster" now but the power falling off at the end concerns me. The car honestly makes about the same power out at redline as the old tune. My peak power dropping off before redline should not be occurring in my opinion. It really is only going out to 7500rpms according to the graph even though redline is set at 7800rpms.

The car jumped 40ft lbs and 20whp over the first tune. Its almost as if there is a restriction somewhere. Greg H, the member who had the motor before me was making 512whp and like 356trq @ 14psi e85 on his setup. Yes I know the turbo setup will change many things but his trq was pretty low when comparing it to my 450 360. Here is his graph not that it really matters:

 

If the 2nd dyno was a loading dyno or had a heavier roller, it can cause you to reach max boost earlier in the power band, this will result in higher TQ numbers and could explain the difference in graphs. Check your logs and see if there are differnce in how boost comes in on the 2 tunes.

 

yes the new dyno numbers on graph 2 was done on a dyno that puts load on the car.

 

Regardless of whether the dyno's where loaded or not. Something is happening at 7200rpms that is causing power to fall off like a freight train lol. Peak hp should definitely be a lot closer to redline than it is. If The trq could have been kept further out this car would have made easily 470whp plus. I wonder if this is the restricted cold side piping playing a roll...?

 

what type of turbo manifold do you have and what type of intake manifold. Also are you running a dumptube?

 

Turbo manifold is a discontinued SFP AC/PS manifold. It has a collector and none of the runners are pointing at each other. It is not considered a log manifold.





As far as intake and dump tube is concerned. The car has on a skunk2 intake manifold and a 2" open dump.

 

I had a similar problem but it turned out to be my dumptube. it was to close to the turbo causing the turbo to suck the hot air back in and my car fell on it's face after 7800rpms.

 

Any other ideas?

 

Leigh, i know its a little late but i just caught drift of this thread.

The blue graph that you stated was with vtec activated later... Thats not so. That was a run where the car was misfiring and i was not all the way into the throttle. This was before the plugs were gaped tighter

OK
Just take a minute to compare the dyno graphs you posted above. I would like to know what the big concern is here? Look at the torque on the previous graph before you brought the car to us. Pay attention to it from 2500rpms on up to 7500rpms.

Now look at the torque graph in between those rpms on your most recent dyno graph. You have more torque all the way throughout your rpms. Given this is going from one dyno to another. I can argue that to an extent. Recently our dyno has been proven to be right on par with the one your car was previously tuned on.

So this brings me back to this... Your power band has not drastically changed for the worst like you seem to make it out in this thread. Yes you would be better off if your torque would have held flat all the way to red line. Unfortunately there is quite a few factors that can keep such a thing from existing. Some of them being burn efficiency, volumetric efficiency, timing, and exhaust limitations. Your air/fuels are on point, you don't have any misfires, and timing isn't enough to flatten out your torque graph.

I'll just stop right here..

As i was once told
"why hire a dog if you, yourself plan to do all the barking?"

-James

 

OP: on your "flatter" torque curve you had boost creep, and on the other you had less boost and boost was falling off. see where im going with this?

im not sure how a tune can affect your boost levels, i could be wrong. ive never heard of such an issue

 

Whats the turbo?

More power being made means there's also more exhaust being expelled. Something in your exhaust is starting to become a restriction would be my guess. Also, what CoreyR said.

Don't worry about peak hp, worry about the total area under the curve.

 

It can, just not super-drastically.

Hell, ask Ken Peak of Peakboost. He seems to think you can tune out 12+psi's worth of boost creep on one of his junk K-Series manifolds using a large turbo and a single, poorly-placed 44mm gate.

- Derek

 

For beginners the intercooler piping and exhaust on this car could use some major help. He would gain from a better flowing exhaust manifold as well.

 

its not just his..they all do with single 44mms on k series from what I've seen.

(only expierence with AFI and full race single 44mms on 35r)

 

lol

 

LOL

tell us how you really feel.

 

How about revving the car to at least 8. The graph doesn't show that

 

the sharp down turn on the 2nd graph looks like whoever was running the caron the dyno eased of the throttle or hit a rev limit (graphs look like that when i'm on a mustang dyno and hit a rev limit or something limits power)

short of a catastrophic failure nothing will cause that sharp of a decline (well a closing throttle too).

i'm willing to bet the lumpy torque curve is timing and the 2nd graph is compressed horizontally making it look uglier

also comparing results from 2 seperate dynos is kinda pointless; there are so many varibles involved there at the very least you would need to compare both tunes on the SAME dyno to see the differences

 

also valve float. its a possibility.

very true.

 

The downward slope at redline.. thats just dynocoms software. Even with the smoothing turned all the way down it still somewhat resembles that

 

true valve float but @ 7500rpm even a bone stock high millage d16z6 head shouldn't be floating there may not make power for **** but isn't near floating territory just yet

/edit: idk why i put z6 i was thinking this was a single slamer... concept still applies 99% of honda motors can spin 7500 and not be near valve float land

 

it can easily happen if you arent very experienced (cough myself) and end up getting valve springs without the required exhaust side seats/spacers, leading to valve float at 7100rpm.


it was quite a surprise when a stock head resisted float much past that point. LOL

expensive and slightly embarrassing lesson learned.