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-   -   Stock nikki carb + autocross (https://www.rx7club.com/race-car-tech-103/stock-nikki-carb-autocross-727364/)

cletus 02-04-08 11:01 AM

Stock nikki carb + autocross
 
What is everyone's experience with the stock 1st gen nikki? As I'm finishing up the rest of the car prep for the year, I'm starting to worry if the carb is going to be a problem with stuttering/dying with hard cornering. I've read a few things where people have had small stuttering issues, but my only experience is when I drove a different 1st gen many years ago, it would actually just die and not restart for about 10 seconds. But I think that car had other problems. This one has a much better suspension set up though, so it has gotten me worried lately.

The obvious follow up question is are there any easy solutions if there is a problem? The plan for the car is eventually IT, so everything has been done according to those rules so far. Carb choices for IT are extremely limited, so most folks stick with the stock for that.

Unfortunately, this is a really difficult thing to test safely on public roads.

Probably should have thought about this earlier.....
Thanks

Kentetsu 02-04-08 11:49 AM

I never had any issues with the stock Nikki while autocrossing. But, if the rules allow any modification to the carb, you should definitely talk to Sterling. He modifies carbs and they come back as a work of art! :)

Check this thread for more info and links to contact him if interested:
https://www.rx7club.com//showthread.php?t=725550

cletus 02-04-08 12:28 PM

I will be doing a sterling in the near future, but there isn't much that's allowed to be done to it. Pretty much just stripped down.

mazda6guy 02-04-08 05:30 PM

I have no problems with my Nikki neither while autoxing. Just replaced my fuel pump because the factory one was very weak and the Nikki performs 10x better now. Replaced it with a Holley blue fuel pump and FPR and set the fuel pressure to 3.5.

Kentetsu 02-04-08 10:21 PM

Here's a short video of my car at one of the last races of the year. She smokes a bit due to being plain worn out (well over 200k on motor), but no fuel delivery issues even in the hairpins. First run is shot externally, 2nd is in car. This is with a Sterling carb:

http://www.youtube.com/watch?v=jB-JDdINMzU

MtotheIKEo 02-04-08 10:23 PM

mine will stutter when going through constant left hand turns, but it fine otherwise. I think it is a float problem though.

Kentetsu 02-05-08 08:12 AM

Mine did that when I had the fuel pressure set too high...

Chedstar 02-05-08 11:07 AM

I run a stock Nikki on my ITA car built by Paul Yaw. He suggest running about 2 to 2.5 psi. I sometimes run into problems on the long straights at Portland International, with the fuel pressure being so low and bottoming out.

Kentetsu 02-06-08 08:58 PM


Originally Posted by Chedstar (Post 7829621)
I run a stock Nikki on my ITA car built by Paul Yaw. He suggest running about 2 to 2.5 psi. I sometimes run into problems on the long straights at Portland International, with the fuel pressure being so low and bottoming out.

If you are running out of power on the straights, I would suspect a weak pump, restricted system (fuel filter?), or low float levels....

Zyrano 02-06-08 11:55 PM

My car studders every once in a while on hardturns at autoxes, but it happens rarely. I have some custom work being done to hopefully solve this problem, but there's no way you will be able to do it with it rules...

Chedstar 02-07-08 10:44 AM


Originally Posted by Kentetsu (Post 7836501)
If you are running out of power on the straights, I would suspect a weak pump, restricted system (fuel filter?), or low float levels....

I guess I did not word that correctly. Always had power, but the low fuel pressure light would come on, and see I was starting to bottom out on fuel pressure. Engine always ran strong, the full length of the straight. I am running two Carter pumps, with new filters, separate lines until just before the pressure regulator. You raise a good point about float level, I will check if after a long run at higher RPMs.


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