Maximizing Dyno results on NA car - HOW ?

[MvM]

I have been asked by a Dutch car magazine to participate in a run of articles they are doing about putting someones car on a Dyno and then publicizing the results.

And of course, I want to make a good impression

My car is a '98 NSX-T with only the following mods (related to the engine that is):

- Cantrell Air Intake
- UNIFlow filter
- Taitec Headers
- Taitec GTLW exhaust

If I want to make sure I get the maximum dyno output, what can I do to do this? I have thought of the following things so far:
- Using 98 octane gas (instead of the 95 octane I am normally running)
- Clean the UNI-flow filter a day before testing
- Make sure oil level is at the right level
- Make sure the airco is switched off when doing the dyno run
- Make sure the dyno shop positions a fan at the air intake as well

Does any one have any other suggestion that might make a (small) difference.
(difference as in increasing output, not diminishing it).

 

[dablackgoku1234]

Are you planning on adding additional mods to the car prior to dyno'ing? Like, RDX injectors, AEM FIC, etc...

 

[Vega$ NSX]

Running higher octane isn't really help unless you have a way to adjust the A/F ratios to take advantage of the higher octane.

One thing I would recommend is to lower the intake temperature as much as possible. One easy way to do this is to rest bags of ice all along the intake side of the engine all the way up to the intake manifold. Also put bags of ice in front of the fan blowing directly into the intake.

 

[Sumeronthechain]

Depending on how serious you were about getting every last HP

1. Remove accessory belt(s)
2. Remove air filer
3. Use a thinner weight oil

 

[e.pie]

Depending on how serious you were about getting every last HP

1. Remove accessory belt(s)
2. Remove air filer
3. Use a thinner weight oil

Removing the air filter does nothing, I did a back to back dyno pull through the stock intake and an open throttle body, there was zero difference.

Removing the belts won't really do anything either because there are only 2 accessories, the A/C which does nothing unless it's on, and the altenator, which is a negligible amount of drag.

 

[RYU]

On an NA motor this is what I would do. This is assuming no compromises for a street driven car needs to be made. If I had another NSX i'd love to play around with these mods myself!

1. Swap to a lightened flywheel. Tilton or Fidanza
2. RDX Injectors at whatever PSI most people run on here.
3. You're using 98 octane which is great. I'm not sure if that's the same measurement standard as what we use here in the US but i'm going to assume it's better than the 91 we have here. I'd go with a AEM EMS so you can manage the injectors and up the timing. You cannot advance the timing with an F/IC.
4. Quality headers like Comptech, Fujitsubo, etc.
5. Wide open 2.25" exhaust with no X-pipe. Run each chamber independent. If you run an x-pipe make sure the collector is efficient.

I'm on the fence about removing the stock airbox. If you can incorporate a big velocity stack it will help. L_Rao has done much research on this but fitment will require some creativity.

 

[Mac Attack]

Shh,

http://www.prostreetonline.com/x/nos-sneaky-pete-kits.asp

J/K! C'mon, I live in NASCAR country

Dave

 

[MvM]

Thanx for all the replies so far.

I will NOT be able to modify anything else on the car. Basically, the idea was to get the cars as close to stock as possible. The engine itself hasn't been touched at all, so the intake, headers and exhaust were probably deemed admittable anyway.

Adding things like different injectors, AEM to advance/adjust timing etc. simply isn't possible. This dyno will be done in two weeks time, and I am far too busy to change anything on the car. Still have a Autorotor CTSC that needs to be installed but I will do that after this dyno. At least it will give me a nice baseline to start with.

 

[RYU]

Shh,

http://www.prostreetonline.com/x/nos-sneaky-pete-kits.asp

J/K! C'mon, I live in NASCAR country

Dave

Best solution thus far!

 

[RYU]

Thanx for all the replies so far.

I will NOT be able to modify anything else on the car. Basically, the idea was to get the cars as close to stock as possible. The engine itself hasn't been touched at all, so the intake, headers and exhaust were probably deemed admittable anyway.

Adding things like different injectors, AEM to advance/adjust timing etc. simply isn't possible. This dyno will be done in two weeks time, and I am far too busy to change anything on the car. Still have a Autorotor CTSC that needs to be installed but I will do that after this dyno. At least it will give me a nice baseline to start with.

Whoops! I misunderstood the intent.

Here's what I would do.
1. Remove the air filter on the dyno run.. shhhhhhhhhhhhh!
2. Run as thin of an oil as possible for the dyno run.
3. Overinflate the tires and use smallest diameter tire possible.
4. Just make sure everything else is in top shape.. i.e. injectors are clean etc...

$0.02

 

[Mac Attack]

If they're after originality, put your OEM '98 wheels back on then, unless you have some lower MOI wheels/tires.

 

[tof]

Running higher octane isn't really help unless you have a way to adjust the A/F ratios to take advantage of the higher octane.

Not necessarily true. 95 octane in the Netherlands most likely refers to RON (Research Octane Number), as it does in most of the world. This equates to 90-91 octane on the U.S. where the octane number on the pump equals RON + MON divided by 2. (Motor Octane Number or MON will be much lower than RON for a given batch of gas. It's just a different way to measure knock resistance.)

95 octane RON would be about the same as the crap premium our brothers in California are forced to buy. Here in the south we run 93 octane, which is equivalent to 96 octane RON in Europe.

Of course if the engine has zero knock on 95 RON then filling up with 98 RON won't produce any benefit except to the gas station's profit margin. But your ear can't detect the small amount of knock that might cause the ecu to retard timing and/or enrich the air-fuel ratio a bit, either of which will reduce power a little. So for a one-shot deal like this, it may help to run the good stuff. It certainly won't do any harm.

 

[tof]

Oh, and if you have any control over this, have the dyno runs done under the coolest conditions possible, like early in the day. This could make a bigger difference than all this thread's other excellent suggestions combined.

Cool air is more dense than warm air. The mass of oxygen stuffed into each cylinder dictates the amount of fuel that can be burned per combustion event. The volume of air your engine can take in depends on things you don't plan to change like the design of the engine, intake, and exhaust systems. So more dense air, which contains more mass in a given volume of air, will provide more oxygen in the cylinders, which means more fuel gets pumped in, producing more power.

 

[E-Nough Logic]

I hope most here realize that unless the lower octane gas is causing knock then higher octane gasoline actually produces less power. Higher octane gasoline keeps the cylinder cool but also takes longer to burn. So if you run the same timing on both octanes then the higher octane would take longer to reach peak cylinder pressure similar to retarding timing.

 

[goldNSX]

98 octane gas won't help you at all in a stock NSX. If the engine has been construced for it it's necessary but the NSX has a 10.2 compression ratio. 95 octane gas will give you better results as it fires better. With a CTSC you need 98 (if it will be mounted this decade). :wink:

The car has to be stock? Well, cleaning the air filter is ok. Get the stock injectors cleaned and balanced (EUR 100-150). During the dyno keep the rear hatch open. Maybe 5 hp to find.

You asked where you can gain. I'll turn it the other way round: how to minimize loss -> most importantly the tires. Get fresh rubber on it. Lower the tires pressure a little bit but be careful. Set camber to zero, toe to minimum within specs.

My observations go as follows: before my CTSC aera we did dynos in 4th gear with cold tires and near to no slipping. With CTSC we needed 120 kg in the trunk and two passengers in the car and were only able to run a reliable dyno in 5th gear (yes, despite the low numers the car really IS powerful ). With hot tires we could do it in 4th also.

You owe us a dyno. Good luck!

 

[tof]

98 octane gas won't help you at all in a stock NSX.

See my post above. He is in the Netherlands so gas labeled 95 octane at his local gas station is the same (octane wise) as our 91 octane.

 

[goldNSX]

See my post above. He is in the Netherlands so gas labeled 95 octane at his local gas station is the same (octane wise) as our 91 octane.

No problem, I was referring to Maarten's question directly.

 

[dirtbag]

RYU is right. Over inflate your tires. I've seen up to 3% difference between under/over inflation. The compound also makes a slight difference, but people would make fun if you sported some rock hard fuel economy tires.

 

[Dutchy]

Very curious to see the results.... I recently put the exact same setup on my NA1...different brand headers though.

Wich magazine are you talking about?

 

[MvM]

Thanks again for all the advice.

The dyno will be done on June 7th, in the morning. Hopefully it will not be to warm that day (and dry).
I am very busy with work at the moment so the only time I have is in the coming weekend and some evening hours (when I'm not otherwise occupied).
So changing alignment.

I am planning to run a bottle of injector cleaner through the car this week.

I did fill up the tank with Octane 98 once now. Don't really feel any difference, but I do seem to get some better mileage.
Am not sure though if that means anyting. Am not sure about the comment about 98 Octane producing LESS power than 95 Octane. Goes against practially everything I have read/learned so far. AFAIK, the ECU of the NSX should be able to advance timing with higher Octane fuel for just a little gain.

Am not sure about the tires.
RYU says OVERINFLATE, but GOLDNSX is saying DEFLATE your tires.
I suppose is has to do with grip?

I am running 265/35/18 tires now on OZ Ultraleggera wheels. Tires are good for about another 2000 miles.

For GoldNSX, yes, the CTSC will be mounted this year, I promise.

Dutchy, the magazine is called Autoweek. Not the best of car magazines as these go, but one with a very active website. They did a short video item on the new NSX with Mr. P.P. and me in January also.

 

[goldNSX]

Am not sure about the tires.
RYU says OVERINFLATE, but GOLDNSX is saying DEFLATE your tires.
I suppose is has to do with grip?

Yes, grip. I respect RYU's observation. But less pressure, more grip, less slipping.

As for 98 octane (sorry, only in German): http://www.adac.de/infotestrat/tank...zin-und-diesel/premiumkraftstoffe/?tabid=tab2

98 versus 100 octane. The differences are well within the standard deviation of dyno runs I believe. 98 doens't offer more energy, it only resists more to knocking.

 

[tof]

I did fill up the tank with Octane 98 once now. Don't really feel any difference, but I do seem to get some better mileage.
Am not sure though if that means anyting. Am not sure about the comment about 98 Octane producing LESS power than 95 Octane. Goes against practially everything I have read/learned so far. AFAIK, the ECU of the NSX should be able to advance timing with higher Octane fuel for just a little gain.

Right, and right. IF your knock sensor picks up any knock whatsoever on 95 octane* then it will retard timing and possibly richen the air fuel mix. Either would reduce power a bit. But hybrdthry911 is technically correct. The slower burn of higher octane gas is what helps it prevent knock, but it also means a bit less power. So you really have a balancing act...less power because of the slower burn, but more power because absence of knock means more advanced timing and leaner air fuel ratio.

If you see an increase in mileage it could mean the trade-off for your car is in your favor. Of course if the difference in mileage is small, and only computed based on a couple of fill-ups, it could be the result of other factors such as differences in driving conditions between the two tank-fulls.

Am not sure about the tires.
RYU says OVERINFLATE, but GOLDNSX is saying DEFLATE your tires.
I suppose is has to do with grip?

This is another trade-off. On the one hand, lower tire pressure will reduce slipage on the dyno drum and will result in higher HP readings. But I don't think peak HP would be affected unless there was some slippage at peak HP rpm. This seems unlikely but not impossible.

On the other hand, an over-inflated tire and/or a harder compound would reduce rolling resistance (friction). Since rolling resistance decreases the HP numbers produced by the dyno, reducing rolling resistance will increase the HP numbers....as long as you don't over-inflate to the point where you increase the tire's diameter to the point where the final drive ratio is affected. That seems unlikely unless you just go crazy on inflation pressure which would be dangerous anyway.

Good luck on the dyno pulls. We are all looking forward to the results.


*For those who haven't read every post in this thread, this reference to 95 octane is based on EUROPEAN octane rating systems. 95 octane (europe) would be the equivalent of 91 octane in the US.

 

[goldNSX]

This is another trade-off. On the one hand, lower tire pressure will reduce slipage on the dyno drum and will result in higher HP readings. But I don't think peak HP would be affected unless there was some slippage at peak HP rpm. This seems unlikely but not impossible.

On the other hand, an over-inflated tire and/or a harder compound would reduce rolling resistance (friction). Since rolling resistance decreases the HP numbers produced by the dyno, reducing rolling resistance will increase the HP numbers....as long as you don't over-inflate to the point where you increase the tire's diameter to the point where the final drive ratio is affected. That seems unlikely unless you just go crazy on inflation pressure which would be dangerous anyway.

On my dyno - and I guess MvM is using a similar one - they calculate the engine power by adding the power measured while accelerting to the power lost by rolling resistance AFTER the first one has been made. In this scenario, if you overinflate the tires you get more slipping (less power) and have less power added by lower rolling resistance. With lower tire pressure you get more power due to more grip and get higher power from rolling resistance. Both effects add to more calculated power, well on the sheet.
Just be careful not to go too low as the tires are spinning pretty fast on Europe dynos pretty long too.

Overinflating tires is for hypermilers only. :wink:

 

[tof]

You make a good point that I meant to include but neglected to do so

The impact of tire pressure on hp readings will vary from dyno to dyno, depending on the make of dyno, surface of the drum, dyno procedure, and even how tightly strapped down the vehicle is. Of course if you hook up to one of those dynos that bolt to the rear wheel studs rather than using a drum, then tires make no difference at all.

One final caveat about this topic: To butcher an old saying about figures, dynos don't lie but liars dyno. The operator can produce a wide variation in results depending on the adjustment factor values he sets up.

 

[Sumeronthechain]

Yes, grip. I respect RYU's observation. But less pressure, more grip, less slipping.

While its a valid theory, I don't think the NSX without a power adder is going to be spinning any tires on the dyno.

Over-inflate, IMO. Also, use the lightest wheels you have access to.