what is the best spark plug?

[copteaser]

Can someone tell me which spark plug is best for high boost? (23lbs of boost with alky system)
thanks

 

[TurboJim]

I have had nothign but good luck with R43TS gapped at a tight .035 to 25psi, then .032 above that, but idle quality suffers with tighter gaps

 

[salvageV6]

What Jim said.

Use the CR43TS if you want a good heavy duty ground electrode like the old A/C plugs used to be made with.

C in the designation means commercial.

Pep Boys had them up here.

 

[U1ARUNIT]

NGK?

Anyone ever run the NGK UR5 plugs? If so what are ya gapping them to when running 25+# boost? Thanks..

 

[d0n_3d]

i use ac delco cr43ts plugs gapped at .035" and have no problems with them...they are very heavy duty and can handle high boost...autozone carries these as well as advance auto or pretty much any auto parts store...if you are running in the mid to low 11's or faster i would recommend cr42ts plugs especially for a mostly race only car

 

[Eric Stage I]

I run NGK TR5's on my 4.1 car. It has GN1 heads, that's why the TR5 instead of UR5. I am real happy with their performance. I've had them on for about a year using leaded race gas with no problems. However, I'm alittle against the mainstream on spark plug gaps. I've run a .025" gap on my car for about 10 years with no issues, no idle quality problems. The bigger the gap, the more voltage it takes, and the shorter you're ignition system components last. In track testing, I've found no horsepower penalty from a smaller gap either (I've not tried smaller than .025"), just smooth high boost runs on the original 15 year old coilpack.
Just another opinion to throw in...

Eric

 

[TurboJim]

Originally posted by Eric Stage I
The bigger the gap, the more voltage it takes, and the shorter you're ignition system components last. In track testing, I've found no horsepower penalty from a smaller gap either (I've not tried smaller than .025"), just smooth high boost runs on the original 15 year old coilpack.
Just another opinion to throw in...

Eric

The problem doesnt lie in HP/small gap, the problem lies in a lean mixture (14:1) and a small gap not having a large enough flame kernal to successfully light off the whole charge.

I'll bet you a million bucks, you put your car on an emission machine at .025, then .035, the .035 reduces HC by 1/2 and I BET your idle is smoother.

BTW: your TR is designed to use a .035+ gap. Dwell is set for it, you wont hurt anything by opening the gap, thats total BS.

 

[bruce]

Originally posted by Eric Stage I
The bigger the gap, the more voltage it takes, and the shorter you're ignition system components last. In track testing, I've found no horsepower penalty from a smaller gap either (I've not tried smaller than .025"), just smooth high boost runs on the original 15 year old coilpack.

No penalty, but no gain.
If you run larger gaps you can run LESS timing. Less timing less chance for detonation.

There is evidence that the 60 and 80 thou air gaps were harder on ignition components, but I doubt you'll see any real signifigant changes at going from 35 to 25. using a 3 or 5 gas analyser as Jim mentions will show an increase in emissions, which is an indicator of a poorer flame, due to the smaller spark.

Good reading material is, The Doctors guide to Optimizing Your Ignition System. Ignore the hype for his ignition stuff, and the core info is good.

 

[Chris Taylor]

Jim is right, a tight .035 gap is the proper gap. I use Autolight 23's and AC R43TS with a tight .035 with great performance.

 

[Eric Stage I]

I figured I'd get jumped on for the .025 gap thing...
Jim, I'll defer to your emissions testing experience here, as I've never had to deal with emissions testing.
I agree that it has a large affect on emissions and I agree that .035" is the "proper" gap for these cars. However, I believe that when you start running 20-25psi boost things change alittle. It seems like once a day someone on the board mysteriously develops a misfire when they turn their boost over 20 and then 12 people say "replace the coilpack". Why not just drop the gap alittle and tax the coilpack alittle less? (Unless you have emissions test to deal with.)
Not trying to BS anyone, just relating my experience with my own cars.

Anyway, back to tuning the FAST system. I just stuck in some 84# injectors and they're touchier then the 52's I took out. At 23psi boost, I'm only showing about 50% duty cycle at 11.5:1 a/f. Before it was 95% dc.

Eric

 

[TurboJim]

Originally posted by Eric Stage I
, I believe that when you start running 20-25psi boost things change alittle. It seems like once a day someone on the board mysteriously develops a misfire when they turn their boost over 20 and then 12 people say "replace the coilpack". Why not just drop the gap alittle and tax the coilpack alittle less? (Unless you have emissions test to deal with.)
Not trying to BS anyone, just relating my experience with my own cars.


Eric

Nah, wasnt jumpin dude. Notice I also indicated a smaller plug gap once boost reached inhumane levels? I didnt go as far as .025, but see lots of fast cars (9's and faster) at those gaps. Some even smaller than .025. They cant all be doing it wrong I know what you're saying, but for the average Joe, running 20psi on alky and pump gas (or whatever) I still recommend 43's w/.035 gap.

 

[REDS HOT AIR]

Re: NGK?

Originally posted by U1ARUNIT
Anyone ever run the NGK UR5 plugs? If so what are ya gapping them to when running 25+# boost? Thanks..

I'm running them at .030 gap and never have missfire at higher boost..

 

[S2V6RACER]

R43TS. Ran at .034 and it ran great untill 29psi. I tightened them up to .032 and it pulled good at 30 psi. I will probably try tightening them up on the next round and see if there is any improvements.

 

[DonnieShort]

Re: NGK?

Originally posted by U1ARUNIT
Anyone ever run the NGK UR5 plugs? If so what are ya gapping them to when running 25+# boost? Thanks..

I run them and like them alot. They especially like alky and runs very well. Gap is at . 0315 and purrs like a kitten.HTH



Donnie

 

[galoush]

Ive run Autolite 23s at .035 gap with boost up tp 27psi and c 16 and had no problems .

 

[tim87tr]

Originally posted by galoush
Ive run Autolite 23s at .035 gap with boost up tp 27psi and c 16 and had no problems .

What quarter mph (horsepower) and also boost level do you recommend going to the 23s. I am running the 24s at a tight .035 at 20 psi on a stock turbo. Tim

 

[galoush]

The best qtr ive been able to pull was 12.49 at 113 mph but 25 psi was the boost ive run most of the passes , the 27 psi passes didnt seem to jack up the mph , but it was also hot out 90s and im running a TA49 and stock intercooler with 2 1/2 neck so 27 psi may not be benifitial considering that . But the car didnt missfire at all.

 

[galoush]

The 23s shouldnt hurt with a stock setup , i thing the plug being a little cooler is better than being a little to hot , you could go up a pound or two in boost , run good gas though even at 20psi you should .