NSX vs NSX ( me and my GF's NSX ) why?

[PaulL]

Post the dynos and that might help us.

By the way, the 'theory' about needing backpressure for improved torque is incorrect.

What one needs to improve the torque is a high velocity in the exhaust pipes which will help draw out exhaust gases.
This is obtained by having a smaller pipe, which some people then incorrectly infer creates a higher backpressure which is what helped the torque.

Obviously, there is a point of diminishing returns ... too small of a pipe WILL create a big backpressure, which the engine then has trouble pushing through.

It is the total area under the dyno plot that is important ... not a high spot on one end or the other.

 

[ffffanman]

PaulL, please give us some back up info on that torque and small pipe and drawing out exhaust statement. It is very interesting and I would like to know more! Do you have any links to tech data on this or Books or anything like that.
Just want to get smarter, I know that will be tough but I'm willing to try!!!
Trev - I know a little about everything. Looking to know a little more.

Quote of the day: Where ever you go, there you are!

 

[nsxtcy85]

Vamp is one lucky dude!

I still want your spoiler dammit! lol:biggrin:

 

[my1stnsx]

Maybe shes a better driver!!!!:biggrin:

 

[VampNSXX]

I will try to get the 2 cars dyno as soon as I can but might not be for about 2 months since I have other stuff to do. We might go to the drag strip soon since that is open at nite and I have time then to do it.

But I would like to see what else you guy have to say about this.

 

[PaulL]

It's not the backpressure - it's the velocity!

Lots of info available through Google regarding exhaust scavenging, but here's a couple of useful links;

http://www.ssheaders.com/header.htm
http://www.dsmtuners.com/forums/showthread.php?t=168578

And, our very own FAQ has the right info, too!

http://www.nsxprime.com/FAQ/Miscellaneous/exhausttheory.htm

 

[lowellhigh79]

I will try to get the 2 cars dyno as soon as I can but might not be for about 2 months since I have other stuff to do. We might go to the drag strip soon since that is open at nite and I have time then to do it.

But I would like to see what else you guy have to say about this.

Vamp,

Swap the wheels. You should see a bigger difference because your GF will now have the bigger and heavier wheels.

Regards,

Danny

 

[SexyRed]

I second on the wheels making the difference. I have both volks 17/18 and enkei 16/17 wheels.

I decided to put on the 16/17 enkei because they were a lot lighter. Try lifting the 18 versus the 17 rears. You will see the difference.

Vamp- long time no see.

 

[NimbleSexyXquisite]

Good Troubleshooting!

What are both your weights?

Tires Setup?

As long as you spank her, thats what counts!:redface:

What is you tire setup?, maybe your setup is lacking traction.

Good Luck.

 

[MiamiMermaid]

Woo Hoo!! When'd Piggy get an NSX?? Go girlie!! You guys better invite *Mermi* to the wedding~~

 

[VampNSXX]

Woo Hoo!! When'd Piggy get an NSX?? Go girlie!! You guys better invite *Mermi* to the wedding~~

got it like 4 months ago.

we will invite you.

 

[91 X]

Vamp, who cares if you are faster or not...you already caught her:tongue:


BTW, we need PICS!!!!:biggrin:

 

[John Corbitt]

Rotational mass. Your larger diameter rims actualy slow you down accelerating. They may improve cornering, but require more power to change rotational speed. Even if the rims and tires weigh the same, that weight pushed further out from the center requires more energy to spin up or down.

John

 

[clr1024]

Post the dynos and that might help us.

By the way, the 'theory' about needing backpressure for improved torque is incorrect.

What one needs to improve the torque is a high velocity in the exhaust pipes which will help draw out exhaust gases.
This is obtained by having a smaller pipe, which some people then incorrectly infer creates a higher backpressure which is what helped the torque.

Obviously, there is a point of diminishing returns ... too small of a pipe WILL create a big backpressure, which the engine then has trouble pushing through.

It is the total area under the dyno plot that is important ... not a high spot on one end or the other.

My point exactly why do people perpetuate the "an engine needs back pressure to make torque"

 

[The Kid]

Pics or Ban....:biggrin:

 

[ffffanman]

Just go to his members gallery area.
There is enought to see there and I dont figure it needs to be posted here.
Just my thoughts
Keep it in your pants.
Trev

 

[MvM]

...from a dead stop the 2 cars are head to head up to 3rd gear is when my car is faster and you could see it then.
from a rolling start in 1 gear my car is just a little faster when we go to 2nd gear but not much faster just like 1 feet ahead.
from a rolling start in 2nd gear my car does go much faster and you could see it. I pull from her fast.

my question is why does it vary in different situations? I would think that my NSX should be faster every time because I have more HP than she does but its not so, it faster yes but taking of from 0 to 3/4 of 2nd grear we are head to head.

Re-reading your post again I was thinking again you should swap your wheels with those OEM-ones from your girlfriend and try again.
It's probably the quickest way to find out if they are the most important negative factor. And when you have the time, put them on a scale too.

Second, you mention at which point your car becomes faster, but since you are using short gears, I am wondering if you are talking about YOUR gears or hers.
If YOU are shifting from 2nd to 3rd (short) gear at 8000 rpm and 72 Mph, your girlfriend is still at 7000-7100 rpm in 2nd.
At that point, your girlfriend has the advantage on you because she's still in 2nd and you are already in 3rd.
Then, when SHE shifts into 3rd gear then YOU have the advantage again because at that time you will be at you're engine's sweet-spot whereas she has to start all over again from down low and from a longer gearing.

Perhaps some runs with a acceleration-measuring device like an AP-22 which can tell your acceleration with 10 mph intervals would be very helpfull here.

 

[mcano]

Dude,

Who cares which car is faster and why...SHIT, NOT ONLY DO YOU HAVE A GIRLFRIEND WHO IS INTO CARS, SHE ALSO DRIVES AN NSX!!!!!!!!!!! We're not worthy, we're not worthy..

All Hail The Fire Chief,

Regards,

Danny

Well if the two of you get married, but things dont turn out as planned, the two of you won't have to fight over who gets the NSX!

 

[comtec]

My point exactly why do people perpetuate the "an engine needs back pressure to make torque"

The whole thing behind this is that as you reduce backpressure you change the air/fuel mixture to the engine to the point of the engine going into a lean burning condition. As the engine air/fuel mixture becomes leaner low rpm torque is reduced. Your car was designed and tuned to use the factory exhaust so any reduction in backpressure will affect the tuning of the car.



The funny thing about this thread is that if someone posts about a "kill" on the road you guys jump all over them because they are posting about racing, but not this thread. The only difference here is that it is a boyfriend/girlfriend.

 

[d1 guy]

Can we see a pic of your girlfriend next to her NSX so we know your not just messing with us? Heck lets see your NSX beside her NSX. Itd make a cool pic. Not doubting you or anything, but I have never seen a chick nsx driver.


Also as for the Brian Spilner advice. It is always good to double clutch when going in a straight line. It helps those old eclipse trannys because they dont have syncros. Those old 1950s trans need the rpms matched between upshifts. Everyone knows that the eclipse is the only car that you upshift instead of down shifting when drag racing. That is what makes the double clutch so important. Oh yeah you dont want to blow the welds on the intake, so be careful with that 100 shot of NOS! WHAT AN AWESOME MOVIE.......(Im certainly just kidding).

 

[VampNSXX]

The funny thing about this thread is that if someone posts about a "kill" on the road you guys jump all over them because they are posting about racing, but not this thread. The only difference here is that it is a boyfriend/girlfriend.

we were just trying to see what the diference would be with both cars. We were not doing it to race just to know if all the money put into one car is worth it.

 

[comtec]

we were just trying to see what the diference would be with both cars. We were not doing it to race just to know if all the money put into one car is worth it.

Hi Vamp,

Nothing against you or what you were doing. In my younger day's i was street racing every week. That was more for the guys that pick out certain people who's a$$ they want to jump on.

You are just seeing the side effect of adding the mods to the exhaust when doing nothing for the fuel delivery. Your engine is burning lean at low rpm because the reduced back pressure is allowing some of the fuel to escape the cylinder though the exhaust valve before it closes. The only way to counter this would be to increase the amount of fuel to the engine at low rpm or to add some resistance to the exhaust. Of course if you increase the fuel delivery the car will be considerably faster than if you add resistance to the exhaust but both should help your lean condition. You could try putting the cats back on .

Cheers

 

[lowellhigh79]

Vamp,

Have you swapped wheels and rerun yet?

Regards,

Danny