Running an 85 in IT7 here in St. Louis. Any recommendations for a source of carb jets and pieces?
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Running an 85 in IT7 here in St. Louis. Any recommendations for a source of carb jets and pieces?
7s Racing in California. Tom has them. It seems Yaw won't return carbs or answer the phone anymore.
Give Charlie Clark in KC a Google/call. KC race parts/shop outlet. Charlie is also an E Production 1st gen RX-7 racer.
My car came with a Yaw carb and since he is no longer interested in servicing the demand I copied the mods he made for my spare. I might start offering it as a service if there is enough interest. Personally, I think I did a far better job than he did.
Anybody know much did Yaw charged back when he was doing it? Or better yet what would it be worth to have your carb modified?
On Edit: David and Jake, after Googling both of your suggestions I still came up with nothing. Do you have any better descriptions that will not result in 40,000 matches?
Tom, the 12A ITA carb Paul built for me cost $365.00 ???
Owned by Charlie Clark
http://www.kcraceware.com/images/kcrace.gif
KC Raceware will get you to Charlie Clark.
I think 7's Only is who Jake is referring to
Sterling Carbs or PBandJracing.com is another source... and Bud, Carl @ PB&J is who built the carb... I can dig up his email if you need it. There's a link to his site on my sites links page ;)
Tom, I have been hoping someone would try to duplicate Mr. Yaw's efforts. Seems there is a real void in Nikki mod capability in this country and with a large contingent of carbed 7 racers out there it might make some sense to invest in this in some manner.
As far as pricing goes I seem to remember paying around 350 for his carb modifications. Along with that you needed to purchase the specified fuel pump and regulator. It certainly did not break the bank but the total including shipping seemed to be between 450 to 475. Another thing he did was to jet the carb for the customer's particular geographic area and provide extra jets with some basic tuning information.
Geez you guys type fast! Thanks Scott for the info. I will take a look. I will be working on the car tomorrow morning getting the trailing ignition fixed up and starting on the brakes too. The only reason I am worrying a bit on the carb is how badly the performance dropped off in last weeks race the last lap and a half. I suppose a dead ignition system did not help! The car is really running a bit rich so maybe getting the ignition right will cure all of my problems. I do have the stock carb we took off the car and that also got me to thinking about carb overhaul and modifications.
Mazdatrix can also supply the jets.
I'll give em a shot, thanks!
We're running the Sterling mod from PB&J and one of the things that's changed is it uses Holley jets. I think the Sterling carb is now at 465 cfm.
And by the description of what is done to make it so it is also illegal for use in IT.Quote:
Originally Posted by CSPRX7
Whats the "Sterling mod"? What class do you run, C Street Prepared? (Assuming from your handle)
The link for information on Sterling is:http://www.sterlingmetalworks.com/sterling.htmQuote:
Originally Posted by lateapex911
and, yes, I do run CSP in SCCA TT - Level 4 (Hill Climbs). CSP is basically unrestricted in carb mods. However, I lurk here because we (my brother and I) are preparing an '85 GSL/SE for IT. It may eventually find its way on to a track.
All by itself, and considering nothing further, the modification of the secondaries from vacuum to mechanical operation makes an IT carburetor illegal.....the operation of the secondaries is checked periodically e.g. at the 2007 SIC where, upon arriving at post-race impound, we were confronted with "Gentlemen, please pop your hoods and remove your air cleaners.".......
I would also be of the opinion that machining or removing internal components to reduce restrictive frontal area e.g. throttle butterfly shafts and/or enlarging venturis would also be in fairly prolific contrast to the, umm, basic intent and spirit of the IT section of the GCR's.
I agree and congrats on Rookie of the Year, Gary. What Yaw does (or did) is remove and block off the choke and all emissions BS with epoxy, make the secondary air bleed jets adjustable, change the mains and change the secondary diaphram spring.
I went a little further and helicoiled the top cover bolt holes, replaced the hardware w/10-32 allen screws and blocked off everything by drilling and tapping the existing hole or driving in epoxy coated pins if it was a steel hose barb. Also, the shafts were shimmed when I saw the Yaw carb had damage on all four butterflys near the shafts due to excessive play while they opened and closed . With the butterflies made of brass and the body made of iron the bores rapidly shaved them away leaving rather large holes. I also brazed steel AN male fittings to the supply and return fuel lines.
Yesterday, I installed and ran the first carb and am building my spare this weekend. If anyone is interested I will soon offer rebuilding your usable core with the above modifications. This also includes a good soaking in carb cleaner (the kind that'll eat your skin off), complete replacement of all gaskets, crush washers, accel diaphram, secondary diaphram, float valves. You will also receive additional air bleed and main jets.
I need to record how long it takes but I'm guessing about $450 would cover the parts and labor. I know that's more that Yaw but the extra machining takes a good bit of time and I'll probably offer it a la carte style so you can pick what you want and pay for it accordingly.
Tom, please keep us posted!
Weber DGV main jets work perfectly in the Nikki carb. The number convention even matches the original jet numbering convention.
I bought my collection from Pierce Manifolds
http://www.piercemanifolds.com/products.htm
Click on jets, emulsion tubes, ... button. The DGV main jets start with Part number 73801. Note that only the DGV main jets work on the Nikki. I am not aware of any other parts crossing over. You WILL need to use the little aluminum washers from the Nikki jets with the DGV jets.
Note that Nikki jets and Weber jets are labeled in 1/100 ths of a milimeter. A #100 Weber jet has a 1.00 mm hole in it.
Yaw labeled his jets in thousandths of an inch. So a Yaw 40 jet has a 0.040 inch hole in it. What was nice about the Yaw jets is that they had a taper seal, and did NOT need the aluminum sealing wahsers...Nice.
My $.02 on Nikki tuning: a clean and proper functioning stock Nikki with smog equipment removed runs quite well with a 97 primary and stock secondary. The secondary can be adjusted +- 1 or 2 sizes depending weather and tuning (stock primaries were 92 or 93 depending on year- I don't remember the stock secondary size it might be 140??). In their stock trim with racing beat style header, the carbs are fairly mixture sensitive, and will lose significant power if just one jet size too rich on the secondaries. Err on the lean side with the secondaries.
With modifications of the emulsion system, both primary and secondary jetting can go up 2 to 4 jet sizes. Done well (ie Yaw) the carb is quite forgiving when even 2 jet sizes rich. Not done well, the carb gets even more finicky than stock.
Happy Tuning!
Tak
ITA #29, SFR
Tom at "7's Only" http://www.sevensonly.com/ is the only place to go for a Nikki rebuild. AND parts including jets. AND incredible customer service, advice, consulatation. Tom will build (or rebuild) a carb better than Yaw and is almost always availale for consultation on how best to adjust jetting for track conditions, including race days when you are at the track. He is THE BEST source for performance Mazda racing parts and instruction on how to utilize same to your best advantage.
It seems we are acquiring a large database of information for carbs here. Thanks for the tip!
You guys might want to contact Roger Mandeville @ mandeville auto tech. in spartanburg,s.c. 864 582 0038 about your carbs and parts.
For those that don't know the name he was racing mazdas back in the champion spark challenge in an RX3 and won several many times for mazda in IMSA and then went on in RX7s. they are great people to work with and know niki carbs very well and will only do legal things.