What type spark plug tip with boost/N2O application???

As the title says. What type spark plug tip is better with a boost/N2O application? A projected tip or non-projected tip spark plug. Thanks.

Ken R.

Non projected.

So 1racerdude, why non-projected over projected? Just curious. I've never ran a non-projected plug but now i'm running more boost and n20 on a stroker and I think i'm having issues with my current plugs, which are projected AC's 1 heat range colder then stock (R44LTS6) and gapped at .035. I have a set of NGK's that i picked up yesterday that are 2 heat ranges colder but are projected also. Wanted to find out the scoop before putting them in. My buddy is running a high boost stroked mustang turbo on the bottle and had to go to a non-projected plug way colder then stock gapped at around .025. He was having the same issues as me. You happen to have a number to maybe an NGK or Autolite 2 ranges colder but non-projected? Thanks for the reply by the way.

Ken R.

So 1racerdude, why non-projected over projected? Just curious. I've never ran a non-projected plug but now i'm running more boost and n20 on a stroker and I think i'm having issues with my current plugs, which are projected AC's 1 heat range colder then stock (R44LTS6) and gapped at .035. I have a set of NGK's that i picked up yesterday that are 2 heat ranges colder but are projected also. Wanted to find out the scoop before putting them in. My buddy is running a high boost stroked mustang turbo on the bottle and had to go to a non-projected plug way colder then stock gapped at around .025. He was having the same issues as me. You happen to have a number to maybe an NGK or Autolite 2 ranges colder but non-projected? Thanks for the reply by the way.

Ken R.


No numbers on the overseas plugs,I use Champions.
The long nose plug is easier to blow the fire out from the boost and they don't transfer heat as well as recessed nose. Boost is the same thing as NO2. More prone to detonation also.
.035 should be good enough on the gap if ya are running an aftermarket ignition.
Ya need to get colder than 2 steps.

I run an NGK with an "11" heat range with my boost+N2O combo. The tip is not recessed, but it is flush. Gap is 0.035".

Rich

I have the same exact question. I am running a set of AFR 227 heads on a nitrous motor (300 shot). I am currently running the NGK 5672A-10 (stock number 7942) which is a projected tip plug, but what LR is saying is I should run a NGK R5671A-10 (stock number 5820) which is a non projected tip plug. Do I have this right?

Michael

Non projected, though you need to monitor your plugs and piston crowns as well as how your engine operates to decide if these are really needed.

Rich

If that's the right heat range and part number.
Gap them at .035.
Take a look at rskrause's post above he runs it all and has experimented with it.
I never run two power adders,make enough HP with one.

Wow! So i'm way off on my plugs. So with my LT1 castings, i need to be running a Tapered Seat 14mm x .708" reach, correct? Was just breezing through the Jegs catalog and looking at the NGK's. They list a .460" and .708" reach in a tapered seat but the .408" is the only non-projected tapered seat they list. Would anybody happen to have any of the NGK numbers off hand for the non-projected plugs? I'll start searching the web and see if I can find some but if anyone has them, it would be much appreciated. Thanks for all the info guys. :D

Ken R.

An interesting link on spark plug selection. I don't know enough to select a plug for an engine with a 300-shot, so I let the pro's do it on an engine dyno, and ended up with a Champion S57YC, which appears to be a slightly projected nose plug.

http://www.childs-albert.com/catalog/pdf/spark_plugs.pdf

A cross-reference table:

http://www.dragstuff.com/techarticles/spark-plug-cross-reference.html

I have an NGK catalog at the shop, but I am pretty sure it is on-line.

LR: there IS a logic to two PA ;) Allows a very mild cam, HR setup to make huge hp when race gas is added. Turbo can do the same by adjusting the boost. But I have never been a fan of turbos. Can't say why, I just don't like them.

Rich

I have an NGK catalog at the shop, but I am pretty sure it is on-line.

LR: there IS a logic to two PA ;) Allows a very mild cam, HR setup to make huge hp when race gas is added. Turbo can do the same by adjusting the boost. But I have never been a fan of turbos. Can't say why, I just don't like them.

Rich

A Procharger set at 26# will get ALL ya want and idles like an old 30/30 Duntove.So will a dual 500Hp shot each staged of course.One on 400 the other on 300.

5.36 in the 1/8 mile with a 1.26 60" on DR's with the blower. Have yet to see a clean pass on the NO2.

A Procharger set at 26# will get ALL ya want and idles like an old 30/30 Duntove.So will a dual 500Hp shot each staged of course.One on 400 the other on 300.

5.36 in the 1/8 mile with a 1.26 60" on DR's with the blower. Have yet to see a clean pass on the NO2.

26psi is not gonna be pump gas friendly though, IMHO.

Rich

26psi is not gonna be pump gas friendly though, IMHO.

Rich

Ya are correct.

Ok, so I returned the set of NGK's i had to NAPA. The were BR7EF's, which is a 2 heat range colder plug for an LT1 casting as stated in HarrisSpeedWorks spark plug post in the nitrous section. I'm assuming i'm correct in saying that for the LT1 heads, we need a 14mm x .708" reach 5/8's hex plug. But I was checking out the NGK catalog at NAPA and if I read it correctly, it said a BR7EF was a 14mm x 3/4" reach 5/8's hex non-projected plug. Would a .708" reach vs a 3/4 be an issue? Should the LT1's use a .708" or 3/4" reach? I asked him if he could pull up an 8, 9, or 10 heat range in that plug and he couldn't. Don't know if they just didn't carry them or that plug doesn't go hotter then that. Couldn't find what I was looking for cause the NGK book is like a phone book and didn't want to take up too much of the guys time, so i'll start searching online. One more question, would it be better to go with a cut back ground or standard? Wondering about that one too. So Rich, what part number NGK's are you running? Thanks.

Ken R.

I may still be lost about what plug i need but found a lot of good info on nitrous application plug use.

http://www.spark-plugs.co.uk/pages/technical/nitrous-oxide-spark-plugs.htm

Good info on this site....

http://www.spark-plugs.co.uk/pages/technical/spark_plugs_technical.htm

And an NGK code breakdown...

http://www.spark-plugs.co.uk/pages/technical/ngkjpg.htm.

From a lot of the reading i've been doing, seems for a nitrous or boosted or both type of application, you'd want to shoot for a non-projected tip, short ground electrode, non-resistor type plug with a heat range multiple steps lower then stock. Now to wade through numbers.....

Ken R.

http://www.ngk.com/search_char.asp
Build your own.:)

Been all over that site MW. It was very helpful in deciding a few plugs to go with. So assuming I get a non-projected tip with a shorter ground electrode, it seems my only 2 options in a 14mm x .708" taper 5/8" hex is an Autolite or Champion. For Autolite AR474, AR473 and AR472 with heat ranges of 8, 9 and 10 in that order. For Champion, S61C, S59C and S57C with heat ranges of 8, 9, and 10 in that order. Both plugs are non-resistor plugs. Now choosing a heat range. Considering my ride is a 95% street driver, any suggestions on a heat range? Assuming a heat range of 5 for stock, I was thinking an 8 or 9. What do you guys think? I'd have to say that if i compared my spark plug knowledge from this morning vs now, i'm now a spark plug part number expert. :o

Ken R.

Rule of thumb I've heard is drop "1" heat range per 75-100 HP increase.
BTW, why non-resistor plugs? Not planning on using your radio much?

As long as you don't get fouling, there is no benefit to a hotter plug and a lot of potential downside. Go with the "10" and see how they work.

Rich

I'll give the 10's a shot rich. Joe, i'd prefer a resistor plug, but when you get down to those types of plugs and heat ranges, i've found that resistor types are hard to find. I found a Champion and NGK with all the way down to a 9 heat range, but they were projected tips with a standard length ground electrode, which i believe may be a lot of my problem. We'll see how the non resistors work. It may just be a case of finding a happy medium here. Again, thanks for all the input guys.

Ken R.

Won't a non-resistor plug generate enough interference to screw up the sensors and ECU?

I guess we'll find out.... My only other option really if I try for a resistor plug is a Champion RSY9C which is 4 ranges colder from stock but the tip is projected. Looks like the ground electrode is shorter then normal though. Thats what I will most likely go to if these non-resistors cause me issues. I went with Autolite AR472's. Other then the Champion resistor option, after that i'd be going backwards in heat ranges and would have to go back to an NGK BR7EF which is non projected, but longer ground electrode and only 2 heat ranges colder then stock. I think i'm pretty much at trial and error time, but i've learned a hell of a lot in the last 2 days about spark plugs.

Ken R.

Won't a non-resistor plug generate enough interference to screw up the sensors and ECU?

I wondered that myself, but the Champion guys said it should be OK. I've been running the Champion Racing plugs which don't have the resistor and everything works fine. Now, if you then went to solid core wires instead of spiral core supressor types, then you would have a problem on your hands.

And in answer to the question of .708 vs. .750 - .708 is tapered seat and .750 is gasketed. They end up about the same place in the chamber with the appropriate heads, all other things being equal.

Thats nice to know about the non-resistor plug Kevin, cause i chickened out after reading Fred's post and ended up going with the NGK BR7EF. Resistor non-projected tip V plug 2 heat ranges colder. I'd like to go colder but but these in for now. I was only 1 heat range colder before and didn't appear to have any issues. Would methanol injection help some if not running a plug as cold as you'd like due to the cooler EGT's? All the plugs looked ok when i pulled them except the one with the cracked one and the other lean looking one because my wire was burnt. :rolleyes: Glad i decided to do plugs today. So the wire and the cracked plug must have been my miss (i didn't crack the plug getting it out either). Didn't feel like i had that miss on the dyno but that wire had to have been like that for a while just due to the looks of it and the cracked plug had to have been there too. Might have explained some dyno issues i had. Then during the drive, the car kept dying on me, which has also been an ongoing issue since the dyno. Found a bad MSD to stock harness connection. All in all, it's been a pretty productive and frustrating day. :rolleyes:

Ken R.

I have also used non resistor plugs in late model computer cars with no apparent ill effects. Don't use solid wire core it don't work it makes the dash look like an emergency in the control room of a nuclear plant.

I run an NGK with an "11" heat range with my boost+N2O combo. The tip is not recessed, but it is flush. Gap is 0.035".

What actual pn are you running? It almost seems like NGK heat ranges are totally inconsistent across plug designs, so one heat range will mean different things with different designs. NGK’s always seem to be a bit of a pain to figure out.

WRT to cold and non resistor plugs… you’d be surprised what you can get away with with a hot enough coil/ignition box. I ran AR12’s (about as cold as you can get in a non resistor autolite) in a very close to stock TPI engine in between power adders for months and never had any problems. Of course:
- tighter gaps make plugs run hotter, they were gapped tight for use with power adders.
- Non resistor plugs supposedly clean themselves better, as do plugs with hard insulators (Autolite’s are about the hardest, NGK the softest).
- That car had a pretty hot ignition to start with (crane hi-6/LX92)

With that you’d think that I was an autolite fan but I’ve always had best luck with AC or NGK plugs. I’ve found autolite resistor plugs very inconsistent and the insulator’s on their plugs in general are very prone to cracking.

I work with the NGK guys as well as the Champion guys at work (great guys BTW and free plugs as a bonus :D ) and they all are sometimes confused about heat ranges, too. They have the plugs rated on a numerical index from hot to cold, but the part numbers do not always represent a full heat range, and some plugs that cross to another brand fall in between the other brands heat range or span more than one heat range. They typically will run the plugs in our engines, then cut them open with a diamond saw to look at the upper part of the insulator and figure out how hot it was running. NGKs have a wide heat range so they cross to a lot of plugs which makes it hard to pick the right one, but also less of a chance picking a wrong one. Also a wide heat range is a good characteristic of extended tip plugs in general.

Now, as to whether meth/h20 injection makes it possible to run projected tips in a nitrous application, I wondered that myself and do not know the answer because there are too many variables there. But conservative is probably the way to go if you are privately funded and have doubts about getting kitchen clearance for another expensive rebuild :D .

I also run a Crane Hi-6 with a LX-92 coil and I am surprised to see that I can run some pretty cold plugs with no ill effects. Right now I am running Champion C65YC Racing plugs (these are new & no one seems to know the heat range of these), I had some RC9YCs in there a while ago which also worked. I usually cut back the ground electrode to the middle of the center electrode, but the racing plugs come that way already and they haev a heavier shell to prevent any chance of a blowout.

I have no trouble with plug fouling and NGK "11" heat range plugs. My ignition is pretty vanilla. Opti, MSD6, MSD replacement coil. If it were a higher revving combo, I'd consider a more exotic ignition. But it works good up to 6,500rpm.

Rich

Assuming you're using boost only (12-14lbs.) , no N20, what heat range would you select? One to two ranges hotter? Thanks.

Joe, you should start with 2 heat ranges COLDER and if it works, stay there. If they foul after a few hundred miles of putting around, back up one heat range.

Messing with heat ranges might seem like a lot of trouble sinnce our plugs can be a bear to change, but you will learn to do it better during that time :D

Kevin, Thanks for the info. I'm looking to use NGK Heat range of 7. Regarding my earlier post above which wasn't really phrased right, I was wondering how much affect N20 had on plug selection. If I add N20 on a boosted engine, how much colder should I go? If I remove the N20, how much warmer should I go? Assuming I decide to use a 75 shot. One or two heat ranges? It seems to me that the use of N20 requires a colder plug than the same HP level of boost. ps. thanks to the original poster for bringing this subject up.

There are some other threads about plugs worth searching & reading. With Nitrous you still need about 1 heat range colder per extra 75-100 hp over stock just like for boost, but you also should switch to a non-projected tip design. You should run the coldest plug that will not foul out. These are just rules of thumb which are published by the plug manufacturers.

NGK from hot too cold


hottest
TR5
TR6
BP7EFS
R5724-8
R5724-9
R5724-10
coldest

THE -9 works well on high compression 12.9:1 and a 250 shot with total timing in the 23 degree area

Have any of you ever used one of these spark plug heat range tools that was featured in a tech article in the Aug. issue of High Perf Pontiac ( www.determinator.net ) ?

That thing looks like a $129 piece of crap to me.

yea, I couldn't figure out why I think it was bohanz did an artical about it and was so excited... as far as I can tell it's just a mechanical depth guage that reads out on a scale (hot to cold) vs an actual depth, measuring the center ectrode... I don't know how that could accurately tell you heat range.

yea, I couldn't figure out why I think it was bohanz did an artical about it and was so excited... as far as I can tell it's just a mechanical depth guage that reads out on a scale (hot to cold) vs an actual depth, measuring the center ectrode... I don't know how that could accurately tell you heat range.

But, for your $129, you also get a spare cover for it... That alone almost makes it worth the purchase price :blah:

I'll tell you, I'd be one pissed mofo if I bought one of those things thinking I was getting some kind of hi-tech plug analyzing instrument and found out it was just a stupid depth gauge with a book telling you how to read plugs, which is basically the same info that is in every ignition and car manual and is available in any spark plug catalog or web site for free. They got a lot of balls selling those for that much money cause they're going to have some really pissed off customers that didn't bother to watch the whole agonizing video to see how the POS actually works.

It's almost comical to look at the examples they give of the plug with the ground electrode melted off and one with the porcelain insulator cracked off "This plug is too hot. You need to select a colder plug" Well no SHT. They make the guy selling the TB Bypass Kits on Ebay look like a saint.

Reprint from HSW posted at LS1 Tech

Thread – 14mm
Reach - .708”
Socket – 5/8 hex
Seat - Taper
Stock Heat Range: 5
Gap: .060
Plug: NGK TR55 (stock number 3951); NGK TR55IX (stock number 7164); Autolite 764; Denso IT-16 (stock number 5325)

Nitrous (one step colder)
Heat Range: 6
Gap: .035 - .038
Plug: NGK TR6 (stock number 4177); NGK TR6IX (stock number 3689); Autolite 103; Denso IT-20 (stock number 5326)

Nitrous (two steps colder)
Heat Range: 7
Gap: Consult
Plug: NGK BR7EF (stock number 3346); NGK TR7IX (stock number 3690); Autolite AR94; Denso IT22 (stock number 5327)

Nitrous (two and a half steps colder)
Heat Range: 8
Gap: Consult
Plug: NGK R5724-8 (stock number 7317); NGK TR8IX (part number 3691); Denso IT-24 (stock number 5328)

Nitrous (three steps colder)
Heat Range: 9
Gap: Consult
Plug: NGK R5724-9 (stock number 7891); Autolite AR93; Denso IT-27

Nitrous (four steps colder)
Heat Range: 10
Gap: Consult
Plug: NGK R5724-10 (stock number 7993); Autolite AR92



I am running AR 94s N/A and AR93s for juice(200 shot). My Ignition is VERY hot with Four MSD coils and a DIS-4 Plus box running wasted spark. Just in case I always have plugs heat range 5 to 11 on hand ;) Some one ALWAYS needs a set!

Hey Ellis, I'd be interested to know if you see any longer term wear on your plugs from switching polarity on them for wasted spark. If you see anything wierd like ground electrode wear, let us know, OK?

On the other hand, maybe you change plugs frequently enough that you don't have wear on them...

You bet Kevin. we are still getting all the bugg's out. I have heard the plugs will stay cleaner with wasted spark but run much hotter needing the hotter plugs.

Once we finally get the bug's out we may need to go up one more heat range on both N/A and N2O ;)

I can tell you this. Hard as hell to tell when one of the coils is un-plugged at an idle some times ;)