Trying to find out what spark plugs most guys are running in the 500-700whp cars?

 

R5671A -8, -9, or -10 depending on the heat range your setup needs.

 

I'm running the 4554 (R5671A-8) right now but Hondata said I should be running a resistor type plug and recommended a BCPR7ES. This is why my S300 might be freezing up from time to time???


Modified by Sean18337 at 1:21 PM 5/17/2007

 

A resistor plug will cut down on RF noise and will probably fix that problem. The NGK or Denso iridiums work well, just get the heat range that you need.

 

I know the next question I'm about to ask is going to be different for all setups but within reason what HP levels would you jump from the #8 to #9 and so on?


Modified by Sean18337 at 5:43 AM 5/16/2007

 

You have to go by the plug readings, but generally speaking, too cold is just going to foul out faster, too hot can cause pre ignition and engine damage. Always lean to the side of too cold if you're not sure. Your tuner should be able to look at the plugs and tell you if they're the right heat range or not.

 

I tune my own car and have always stuck with the 4554. Is there any info that I can read up on that gives details when a car needs to step up to the colder plug?
I know how to read a plug for detonation, but is the rule of thumb of stepping up to a colder plug when you are detonating with the current heat range when timing and A/F ratios are in a conservative range?

Thanks for your feedback Tony 1

 

Google

 

OK I will do that.
What part #'s do you recommend for the The NGK or Denso iridiums?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">R5671A -8, -9, or -10 depending on the heat range your setup needs.</TD></TR></TABLE>

what is the difference between the R5671A -8 plugs and the R5672A -8

because i have been using the 72's.. ??

 

ok the 72's have a projected tip and the 71's tip is recessed..

so does it matter if its projected tip or not? should i go with the 71's?

 

might have to do that. i actually just ordered a new set of 72's

anyone have any insight?

 

They both work fine.

 

i didn't even know they made 10's....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">R5671A -8, -9, or -10 depending on the heat range your setup needs.</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">They both work fine.</TD></TR></TABLE>

yea i know ive been using the projected tip for awhile now.

but really was just wondering what the concept was between the projected and non-projected tips.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">R5671A</TD></TR></TABLE>

the root of most misfire issues and cam/crank/distributor pickup issues

they seem to be hit and miss though, work fine on my car (B series), tyler's car hates em H or K motor, misfires galore

we have since switched to Denso Iridiums, 31 heat range (10 in NGK world), and they havnnt skipped a beat

 

They don't cause dist. pickup issues with a honda ecu

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">They don't cause dist. pickup issues with a honda ecu </TD></TR></TABLE>

i guess...hard to say, but they do cause misfires on hondata style ecu's
eitherway, keep that as a possibility when trackin down misfires on cars

 

We are running the BKR7's (ngk part#6097). The are the coldest/cheapest resistor plugs that i have seen. With the hondata s300 the onboard logging wigs out without the resistor plugs.

 

Yeah, i've never seen misfires caused by non resistor plugs on the s100-200-300 stuff, just problems with the datalogging. The K series stuff tends to have problems sometimes with non resistor plugs.

 

I have the Hondata S300 and I'm running the R5671A-8 plugs which is a non resistor type plug. Only had issues with a crane ignition in the car. I went back to a stock distributor and have NO problems. But I think I will change to a resistor type plug that way if I run into any misfire issues down the road I know its not because I have a non resistor type plug

What type and part # for a resistor plug do you recommend in a #8 heat range and #9 heat range?

 

So your running heat range #7 in your car and run a 9 sec 1/4 mile?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sean18337 &raquo;</TD></TR><TR><TD CLASS="quote">So your running heat range #7 in your car and run a 9 sec 1/4 mile?</TD></TR></TABLE>

Don't be soo surprised, Freddy Clark has gone 9.68@157mph in his CRX with some 7 heat range NGKs, they worked in his set up with no issues. He has been running 7s for like 3 years now, numerous low low 10 second passes and numerous 9 second passes now. I have always went 8s and higher on 500whp and up but that is me.

 

damn terry... your hittin 9's now?