Disappointing dyno results 370z 7at
 

Recently had the car uprev'ed

Mods are as follows

Z1 intake hoses
K&N drop ins
Invidia cat back

Before figures were 299.7hp , 250ft lbs , after remap 309.4hp and 265ft lbs at the flywheel.

Dyno was a dyno dynamics

Tuner thinks the stock cats are holding it back and agrees it's lower than we expected but has little experience of the auto version .

Is this about right ? Or any other ideas

Put it on a Mustang Dyno (heartbreak dyno) and you would cry. The figures for my stock 370 was around 261/218

I baseline only 265 on dyno dynamics before re map :/

You don't have that many mods... What did you expect to get?

Also, I assume you mean at the wheels?

How did you determine crank horsepower from the dyno dynamics WHP figures? Or is this a dyno that calculates flywheel horsepower from its own wheel hp measurements?

How much did the car actually make at the wheels?

Different dynos read lower or higher. They can all be messed with. Some tuners make their dynos read really high because that way it makes the customer feel good about the extra performance they didn't really get. ;)

Anyway, if you don't know what a 370Z usually makes on that dyno (using the same settings, same ambient temp, etc.) I wouldn't be too concerned, but maybe take it somewhere else to double-check this dyno doesn't read low. Those chp numbers are far below stock - if they were whp numbers, I'd say you did pretty good. :)

Those numbers are fine. Put it on a dynojet to get more easily comparable values -- the OEM cats are indeed holding you back. Get resonated HFC's or TP's and retune.

Search for my username and proven power dyno thread to see lots and lots of details on what to expect in terms of output on a dynojet for that and similar set ups.

EDIT: Wait, in Europe I don't know if there is access to dynojet. Seems like Euro dynamometers are usually rolling road... I would see if you can find data for other Z's (MT or AT) at that particular shop to compare and contrast.

That said, I'm sure your results are in line with everyone else's -- no reason to be disappointed.

When testing a car with my ported parts the customer had cats too. Just an example of what can happen he was 4-5 degrees less timing then mine, and 2 other friends who are catless. and he even had berk HFCs. Conclusion was the cats heat up and hold a ton of heat. That heat creeps back to the motor starting knock which is why we pull so much timing.

I never researched it but I'd be curious if it's the heat more or the flow restriction that kills HP with cats. If it's heat I wonder what a cat does back further like in a mid pipe or muffler. Is it even an effective cat back so far with less temps?

HP is just a number and dynos always vary. Take their results with more than a few grains of salt.

Your butt dyno (how the car makes you feel when you're actually driving) is much more important.;)

yah, it's a good way to get a baseline and post-mod measurement to see the increase.

for a street machine, unless you go forced induction the difference is almost undetectable...hot/cool day could have nearly the same results.
but at least you get better sound.

sound is important.

http://images.tapatalk-cdn.com/15/05...8828662ac7.jpg 2011,base,automatic-speed limiter kicked in @ 156mph...drop in K&N's only


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Before figures sound just about right. I have the same mods(except my exhaust is an ARK) and got almost identical numbers (301whp, tq i cant remember) without a tune and on a mustang dyno. Like some have said: butt dyno is more important than any numbers a machine will tell you :tup:

I also agree with getting hfc or TPs and retune in case you want mo' powa :tup:

Your in the UK and using UpRev?

You should have your tuner get EcuTek and retune using that.

I can also help if you want

John

Not very many mods man. You basically have an exhaust and tune. I know people like k&n's and post maf tubes. I had them and now have Gen3's. Get some HFC's or TP's.

Get a true CAI, MD plenum, LTH and call it a day.
you're only having a catback btw :) so don't expect more ..
before the mods i would say your car was putting down ~285 whp ? with the mods u put down 299 whp ( and that's from the catback ), then after tuning you got 309 whp only and that's because your tuner didn't have enough room to play with so he probably advanced the timimg just a lil bit and maybe smoothed out the a/f ratio.. thats all.

These are not whp figures as I said in my first post this is the calculated flywheel output

This is a dyno dynamics dyno so (I think) the flywheel figure is based on the mode selected the run was done in shoot 6 mode

The measured Wheels figures were (estimated as the graph as hard to read accurately)

245hp before uprev and 255hp after uprev

I don't have a chart showing wheels torque

The tuner knows his stuff and I'm sure the problem doesn't lie with him

Dyno dynamics dyno's are the most common here in the UK , dynojets are rarer and usually more often used by motorcycle tuners