RonD.

I know there is a ton of posts on this topic. 89 Turbo old school LR chipset (circa 2005) Tial 46 adj. FPR running 3 bar 3-4" catless Fabspeed Which NGK BPR6 or 7?

Dave W.

BPR7ES gapped at .026

RonD.

Dave PM sent

RonD.

Forgot to mention my tune is a little rich on full boost 17 psi +/- AFR"s 10.9-11.3 Still ok with the 7's?

RonD.

Plugs on the right are the Bosch WR7 DC that came in the 89 T I purchased last spring 2021 mileage unknown. I did pull them when I first bought the car they were burning nice amber and the car idled and ran strong all season at 16-17 psi AFR's low to mid 11's, on idle 14.7-15 solid. I also should mention I ran some 93/105 mix for 1 track day thus the "reddish" tip/porcelain and the gap as removed .032.

Plugs on the left are, as suggested, NGK BPR 7ES .026 gap I pulled today. NOTE: 1- 5 minute test drive with a couple modest short boost pulls and 3-4 10 minute idle- light revs (I know I don't like idling my car) to test new motor mounts and PS reseal and belt, etc. Based on info should the new plugs look like these?

Dave W.

The new plugs are still too new. Nothing wrong yet.
EDIT!
"The old plugs look like they were running rich."
What I meant to say was that the color of the old plugs shows that the engine is running rich. I didn't mean to imply that the heat range of the plugs has any effect on the tune.

RonD.

Thanks Dave, I was thinking/hoping that may be the case. When winter breaks I'll get a better read. I have a ADJ FPR and in the Spring
(2021) backed psi from 43 to 40 (rail end gauge) per LR and full boost AFR's are still a little fat low 11's with the occasional high 10's. That was with the WR7's and bigger gap due to age/wear I assume. I know it's the chip/tune that's causing the rich condition and ultimately a MAF/MAP set-up is the way to go but that will be down the road a little bit. If the 7's end up running rich or even richer than WR7's is going to a 1 step hotter plug than stock an option or too risky?

Droops83

I would definitely not go to hotter plugs than stock! The one step colder plugs are generally only more prone to foul during cold-start conditions, and once the engine starts and runs, the slightly better insulation of the electrode will lessen the change of spark plug becoming a glow plug and causing pre-ignition.

As long as the AFRs are good and accurate, there isn't much of an additional benefit to "reading" spark plugs anyway, except to identify potential oil deposits or something like that.

RonD.

Thanks for input guys. Droops, what I'm really asking is based on the look and larger gap .032 due to age of the stock heat range WR7's which heat range would you suggest? Stock or 1 step colder or does it not matter and not have any effect on running rich "appearance" of the WR7's I removed?

Dave W.

I just edited my post above to clear up any possible misconception. The plugs don't affect the tune. The engine is still running rich regardless of the plug you use.

Droops83

I don't think the plug gaps will have any affect on the appearance of a removed plug, assuming all else stays the same. Narrowing the plug gap is common in modified turbocharged engines to allow the stock ignition coil to keep up with increased pressure and temperature inside the combustion chambers. I went a step further and installed a wasted spark ignition system on my 951 (which is easy to do with standalone engine management) to allow the continued use of stock plug gaps with increased boost pressure.

RonD.

For what it's worth I do have a MSD Blaster coil.

Penguinracer

They're not too coold.
Those plugs just need an "Italian tune-up!"