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Any of you guys watch Joe Simpson? Holley tuner and teacher.
I watched a lot of his videos when I started learning the Dominator system in my Nova.
Was watching a new one just now. 960 hp LS in a Fairmont.
He pulled a plug to have a look. Gee, extended tip NGK race plug. Isn’t that amazing?
I don't get the point. They make an 8-9-10 heat range projected plug. So if its cold enough its not like it will melt down instantly w a projected tip. But Its still hanging the plug tip out in the CC which every performance turbo book and tuner I know suggest against. Kenny Duttweiler spoke about it on one of his many interviews. Kurt Urban.... Jim Campbell...etc I assumed those cold projected plugs were strictly for NA high compression motors and not power adders?
Ive heard a few say the projected tips idle and run smoother. Jarrett Faggart (Stock48) use to claim he ran TR6's in all his turbo LS stuff because they ran smoother. His cars all ran extremely well, no argument there. I was just always under the impression its less than ideal just adding another possible failure point. So why chance it?
Last edited by Forcefed86; Sep 6, 2025 at 09:41 AM.
The projected tip do idle nicer. I tried BR7’s once and it was notable.
I’ve run the R5724-8 since day 1 without issues.
When I worked at the shop tuning and doing the dyno work I noted that the Hellcats, Demons etc come stock with a very extended tip plug.
Ditto for the supercharged C7 corvettes.
I actually looked up the factory plugs in one of the Lambo turbo models. Same story.
It just seems to me the factories know what they are doing. The ground straps on these are a good 1/2 inch long.
The NGK race plugs that are extended are barely extended. Like 1/8 inch.
I just don’t think the blanket statement that I read all over the place “extended tip plugs have no place in a turbo motor” is incorrect. That’s all.
The projected tip do idle nicer. I tried BR7’s once and it was notable.
I’ve run the R5724-8 since day 1 without issues.
When I worked at the shop tuning and doing the dyno work I noted that the Hellcats, Demons etc come stock with a very extended tip plug.
Ditto for the supercharged C7 corvettes.
I actually looked up the factory plugs in one of the Lambo turbo models. Same story.
It just seems to me the factories know what they are doing. The ground straps on these are a good 1/2 inch long.
The NGK race plugs that are extended are barely extended. Like 1/8 inch.
I just don’t think the blanket statement that I read all over the place “extended tip plugs have no place in a turbo motor” is incorrect. That’s all.
I was always under the impression that cars like the demon/hellcat ran projected plug due to the OEMs BS requirements for emissions, drivability, and fuel economy. So while a a non-projected plug would be “safer” (especially if pushing the envelope with higher than OEM boost levels in a drag racing applications) it would idle dirtier, misfire more at light throttle, and hurt emissions.
Also I believe the C7 is direct injected. That changes things like ideal spark plug location a bunch.
Id be curious what a 7-8 projected tip would do in my setups though. I've honestly never tested it. Def. not against it... Just never really thought to go against the grain and try one out.
Last edited by Forcefed86; Sep 7, 2025 at 02:29 PM.
Agree on the emissions etc. and the C7 bring direct injected having different requirements.
The boss always insisted on Brisk plugs. Very expensive. X16 in a Hemi….
Hard to read, easily fouled.
Fortunately on the C7, no Brisk replacement. So it got NGK. Amazing, the boss says…these are easy to read! Doh
We did 95% Dodge. So there I was, a Chevy guy surrounded by Mopars.
Anyway, do try the plugs I listed above. They are non-resistor, but did fine when combined with the stock ecu.
I think you will like how clean they stay.
Thanks. I'll give it a go and report back. Ordered some TR6's for the non-turbo 13:1 ITB setup. And some 8's for the Turbo setup. I have resisted boots so should be good to go. Really hope they help the ITB setup its always been finicky IGN wise.
Plenty of boosted applications use extended tip plugs, many of them iridium. LSA/LS9/LT4/LT5 came with them from the factory, as do all of the Fords and Dodges. We run extended tip iridiums in the world record C7 (no DI) and they look great after multiple passes.
That being said, a "safer" option is non extended tip. I run the R5671A-10 in my car and we run 8s and 9s of that model in plenty of other cars as they are gasket seat plugs. The R5724-10 is a standard tapered seat plug and is BARELY projected, same for the 8 and 9 heat range versions and I would be totally fine with those plugs as well if the head doesn't seal with a gasket seat plug.
And yes the projected plugs idle better and cleaner, we still prefer using iridium plugs in most street cars up to 1000 rwhp.
I did. I’d say the customer ought to be able to do adequate burnouts now. 😁
I don’t think engine size was mentioned, boost level, timing etc.
I guess he leaves that for his courses.
its a built 5.3, with twins 67/62 with a glide. I was wondering the same thing when I watched it and looked in the comments and the only posted that. He didnt go into to many details. How about the video where he listens to chat gpt to try an tune?
That one I didn’t watch.
I use AI on my phone simply because I can’t turn it off.
For some things it’s great. For other things it’s just plain wrong.
AI is quite literally a trainee at work that screws up so often you have to check everything behind it. Just like a human trainee, this takes longer than just doing it yourself. One day it may graduate to a useful employee, but for now it is worse than useless for most things.
Bracket spacing is different. Buy a converter piece, or just purchase LS3 valve covers. I vote valve covers it is just easier.
Purchase an OEM coil pack harness (I like P/N 12579355 GM/ACDelco) or an after market Michigan Motorsports, etc... offer them. I prefer the OEM because of the higher quality connectors - cheap connectors don't last under the hood and wiring gremlins suck. Albeit OEM stuff is 3x the cost when talking harnesses. You can also cut up your LS1 harness, but by the time you purchase the new connectors and do the job, you may as well have just bough the harness.
If you are picky, load in a dwell table for the coil, but I would keep the stock LS1 dwell values for anything over 3k rpm and the factor ls1 dwell multiplier.
Fin
(picture. LS1/LS6 engine top vs. LS3 engine top conversion)
AI is quite literally a trainee at work that screws up so often you have to check everything behind it. Just like a human trainee, this takes longer than just doing it yourself. One day it may graduate to a useful employee, but for now it is worse than useless for most things.
A lot depends on the grade/model of AI you are using. The free stuff i've used is REALLY bad. It will just state something as fact that is totally wrong. Yet does it in a way that sounds intelligent. So if you aren't familiar with the topic, you assume its right. Its horrible! Also if you tell it it's wrong, it just agrees with you... even if it isn't! Its crazy.
I use a "pay version" OF GPT-5 at work that is leaps and bounds above anything free I've seen. With access to complex math AI like the PYTHON sand box and others, it's pretty amazing and accurate. The ability to upload datasheets, designs, diagrams etc. is also very handy. I can send it a spread sheet and tell it what I want it to do. In a few moments it spits back something that would have taken me hours.
Been working on an exhaust system for my little NA 5.3 with the help of AI and PYTHON to target "f1 like" acoustics. We'll see how it goes. I know it will never truly sound anything like an F1 engine, but if its high pitched and raspy... I'll call it a win.
I did manage to try the extended tip TR6’s on my NA setup. I found after milling my heads .100 the extended tips were a bit close for comfort to the pistons though. Had to use those Moroso plug spacers to get it a safe distance. Cruised it around a bit last night. It idled a good 200-300rpm higher than it did with the non-projected 8’s. I have no IAC or idle control on the ITB setup. Aside from that, I didn’t notice any other changes in drivability. But I assume it has to be burning the fuel more efficiently with that jump in idle rpm. Will pulla plug or 3 tonight and see how they look.
A lot depends on the grade/model of AI you are using. The free stuff i've used is REALLY bad. It will just state something as fact that is totally wrong. Yet does it in a way that sounds intelligent. So if you aren't familiar with the topic, you assume its right. Its horrible! Also if you tell it it's wrong, it just agrees with you... even if it isn't! Its crazy.
I use a "pay version" OF GPT-5 at work that is leaps and bounds above anything free I've seen. With access to complex math AI like the PYTHON sand box and others, it's pretty amazing and accurate. The ability to upload datasheets, designs, diagrams etc. is also very handy. I can send it a spread sheet and tell it what I want it to do. In a few moments it spits back something that would have taken me hours.
Been working on an exhaust system for my little NA 5.3 with the help of AI and PYTHON to target "f1 like" acoustics. We'll see how it goes. I know it will never truly sound anything like an F1 engine, but if its high pitched and raspy... I'll call it a win.
I have a feeling the only way to really get the sound you describe will involve 180 degree headers, which will be a huge pain in the *** if even possible on that car.
I did manage to try the extended tip TR6’s on my NA setup. I found after milling my heads .100 the extended tips were a bit close for comfort to the pistons though. Had to use those Moroso plug spacers to get it a safe distance. Cruised it around a bit last night. It idled a good 200-300rpm higher than it did with the non-projected 8’s. I have no IAC or idle control on the ITB setup. Aside from that, I didn’t notice any other changes in drivability. But I assume it has to be burning the fuel more efficiently with that jump in idle rpm. Will pulla plug or 3 tonight and see how they look.
I have a feeling the only way to really get the sound you describe will involve 180 degree headers, which will be a huge pain in the *** if even possible on that car.
Yea that wasn't in the cards with a cheap budget build. But I'm sure you're right. Even with all that trouble, some of the guys that went with180* headers (or 8-1 collectors) still have a crap exhaust note IMO. That NIVLAC57 guy for example. Poor guys got like 24hours worth of welding and fab work on a beautiful set of 180* headers. Still doesn't sound "exotic" IMO. meanwhile a stock c7 with a Corsa "race kit" sounds beautiful IMO. SO def something to "tuning" it like an instrument vs just getting the pulses right.
AI has me tuning each bank slightly differently with true duals. Using some pretty ridiculous pipe diameters in short runs right off the collector to "resonate" at 475-650hz from 4k to 7k. Then a strategic stepping up with a specific length/style megaphone to keep that "harmonic" and amplify it, while canceling out the Low Freq sound with a few other "tricks". May be total lost cause and sound horrible. But I'll have less than $200 in it and I need some sort of exhaust. So what the heck, I'll give it a go.
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