SPOautos

Right now I'm running 9's all the way around. I was thinking of going with 10.5's all the way around but they are a little pricey. Would there really be any benifit in running 10.5's in the trailing or would I be ok to stick with 9's in the trailing and use 10.5's just in the leading.

Would there be anything wrong with that?

Also, do many of you guys run 10.5's on a daily basis? My 7 is my daily driver, you think I'll have any problems with 10.5's fouling with daily driving to work and just around town?

Thanks,
STEPHEN

Bucrx7

Check out this thread, but IMHO I think it's going to foul quick because you are not running hard enough around town.

https://www.rx7club.com/forum/showth...ght=spark+plug

SPOautos

Yea, I had read that thread and there wasnt much info in there about "around town driving". The last couple post in there someone asked about daily drivers and race plugs and no one answered him about it.

I race quite a bit and drive my car pretty hard but I dont know if I drive hard enough for the 10.5's.

Should I just stick with 9's all the way around? Anyone else try to run 10.5's in a daily driver??? How did it do?

Thanks,
STEPHEN

MikeL

I had the R6725-11 (11's) for about 10k miles with no problems. I have the Jacobs ignition thing and it was street ported.

SPOautos

If I'm running pretty rich you guys think I should stick with the 9's??? I've been reading quite a few posts and it seems like the 10.5's are fine for the street but foul pretty easy with rich tuning. I'm running pretty rich.

Thanks for the posts guys

Later,
STEPHEN

spyfish007

Don't worry about it for daily driving unless you can't get the plug to fire ...

SPOautos

Well I'm going to be racing on them also, I race on the weekends and daily drive to work.

What plug are you running?

I havent talked to you in a while, you in TN or TX? Give me a ring sometime, maybe we can get together or something.

Later,
STEPHEN

AJC13B

Try B10EGVs

A good compromise.

10sec rx7

i run b7em on the street, great plug and never fowel, for the track i use b8egv to b10egv depending on fuel used

RICE RACING

Like AJC13B, I run B10EGVs all the time.

I do not use the cooler plugs due to water injection cooling things very well in the combustion chamber.

The only problem with these colder plugs for me is on acold morning start due to heavy premix they will foul if you do not keep the idle up (around 2000rpm) for the first minute or two...after that it can idle all day long and do stop start driving ALL day and it will not foul a plug.

For the money, I like the B**EGV series plugs.

SPOautos

Rice - Will the B10egv's be ok even if I'm running pretty rich? My o2 is high, like around 1.0 at wot. I'd dont have a dyno or wideband like you guys to keep on the perfect edge all the time. I'm saving up for a wideband but it will be a while before I get it and get tuned better. Should I run 9's right now and 10's later after I'm tuned. I've been running BUR-9EQP and was having a prob with it cutting out around 5500rpms, it just felt like there was no power.

Here is the run down, my car was running rich with a 02 of like 1.0 - 1.05 @ WOT. Every now and then it would break up around 5500rpms but if i let off a little it would be ok. Then one day my 02 jumped sky high to like freak'n 2.0, the next day it flooded and the plugs look like ****, totally black and even have some carbon on them. I dont know if the o2 jumped cause the plugs were no combusting the fuel good or if the o2 sensor just died or what.

So there I am. I'm running the stock 3rd Gen ignition and 14-15psi of boost with the stock twins. I have all the bolt ons with PFC and ungraded fuel system. I however do not have a ignition amp, I prob need to get the hks or something.

What do ya think man. Your the expert

Thanks,
STEPHEN

RICE RACING

My tip to you, is if you are going to run rich like that then you need to invest in a CD ignition amp (msd or crane) on the leading plugs.

Voltage requirements to fire the plugs go up either side of stochio mixture, to the point that the engine will find it hard to initiate a spark especially as the chamber pressure gets higher as well...ALL of this makes it hard for your plug to fire. It can be improved to the extent that it will allow you to run colder plugs if the mixture is leaned off to around 11.8:1 or there abouts.

The situation will be agrivated with higher octance fuels as they require more ignition "energy".

Running a hotter plug will aleviate the problems you will encounter when first applying full power, but with extended use once the plugs clear (especially if circuit racing) you may over heat the plug which inturn will cause detonation.

B10EGVs are the minimum for road racing and can run well if the mixture is not too rich on the stock transistor ignition, for the highest power and saftey margin you realy need to step up to a CDI unit, then you have the best of both worlds, being able to run very high octane & slow burning fuels (like high tolune mixtures) or high lead race fuels with cold plugs and no fear of too hot a plug induced detonation.

SPOautos

Rice, thanks so much for you comments/help!!!!!

It sounds like I need to temporarily run some 9's and after I get tuned or get an amp run the 10's you were talking about. I had a feeling I'd be too rich right now for 10's. I dont drive any long road race events so I shouldnt have to worry to much about getting the 9's to hot. I might just pull a little fuel out and see how it does but thats how I blew my motor last time. I REALLY want to wait for a wideband before touching my fuel.

Thanks for the help!!!!

STEPHEN

RICE RACING

v'good idea...I do not do anything without a wideband, all of my data is pretty much 100% (I calculate out all effects certain mods will have) but I still use the wideband to check my calculations.

On the CD ignition front, be carefull as when you go and up the power of this the fuel burns much better, I have herd of race guys here installing CD ignition and having engine failure due to lean running, so double check with wideband once you install this.

I am going to run two Crane Hi6 and two LX92 coils, ONE CD box and ONE coil for each leading plug on my Mazda, I just ordered the stuff from JEGS (pretty good price, compared to here in Aust) I think this will give the hottest most powerfull spark combination without spending a fortune while still being reliable for circuit/road racing. I will keep you informed once i set up the system.