Hey Guys (and Gals)
Have just been enlisted to help develop an EL Street Stock in the handling stakes but I can't do much more till the Owner gets his stuff together in his new Job and the engine is sorted. So that's why I'm here. He has no time and no one to turn to to sort the engine so if you guys would like to come aboard and help me I'd be mighty impressed. This is my first foray into the Street Stock Class.
Ok so from the start the car was dyno'd and it's sound but nothing real special at 144.9kw @rear wheels.
Ran a couple of Meetings and I scaled the car etc etc. Things were improving in the handling and corner exit drive stakes but then the engine started to foul plugs at idle. They'd clear out on the track and the car went alright.
But this has got worse.
We went from BPR6EY to 5's for the Heats and things were a little better but we went to back 6's for the Feature Races after having a read.

Problem is costing a set of plugs every meeting and all the plugs are exactly the same to look at.

We have changed the Pressure Valve for another s/h unit and it was better (a little different) for a meeting.

The Cat on the car has had the guts cut out and a straight pipe (2 1/2") running thru. We're free to run any size pipe after the firewall as long as it's stock appearing (?). This has been on the car for a couple of years.

Filter is a season old K&N in a std Airbox. Injectors are std as is the Throttle Body.

We borrowed (?) a set of ZGR6B-11 last Saturday night at Latrobe Speedway as we ran out of Plugs. Car went a little harder on these judging by lap times.

Suggestions?

Firstly, what is actually done to the engine?

What ECU is it running?

Has the O2 Sensor been changed?

Not a lot to the engine at all as we are a very strictly controlled class. Engine was freshened up late last season as it blew a Head Gasket. ECU is a std item and the 02 Sensor has been on the car for at least three seasons. The rest is basically a stock engine with a few mods on the Seats and a cam with a Ghia Intake. That's about it.

Plugs develop black Soot on the ring then very rapidly this Soot envelopes the entire plug. Every plug is exactly the same. We did have a miss-fire but a new set of Splitfire leads which were worth 5hp btw sorted that then the fouling started about two meetings later.

The Owner said this fouling thing has happened before but he just kept throwing plugs at it (dumb a**) and I see it quite regularly with the Fords in the Pits but no one is talking how to fix it. They just shrug the Shoulders ..........

Replace the O2 sensor and possibly the MAP sensor.

Ok will do. Anything else have to be done like disconnecting battery?

Changed the O2 Sensor and improvements were stunning. THANKS GUYS!

The things you learn! With the fouling problem we had well we ran out of plugs, so I sent the Driver around the Pits to 'borrow' a set. One of our competitors graciously lent us ZGR6B-11, said 'that's all he uses'. Usually we were about about two lengths behind the quickest car after two laps.
With the Plug and O2 Sensor change we went too being able to have the quick guy being unable to pass for 5 laps until my Driver had a 'bobble' mid corner and let the other dude thru.
Turns out they are the plug used in Taxi's for LPG. Interesting and easy gains.

they are also the plug for the tickford xr6 engines

They are also one heat range colder than std plugs

Ok who's heard of or used these? PGR5A-11 AND PGR6A-11. I wrote to NGK and they said if I liked the XR6 Plugs I should try these too. I'm picking them up in a day or two from my local Repco Store.

We've been using the 5' for Heats and the 6's for Features (20 plus laps). I was getting a blue tip back about 2mm from the end on the Ground Strap using 5's for Features. So running 6' in the Features cured that heat thing that was going on. I'm interested in running the PGR 5 and 6' but unfortunately we're at a different Track for the next two Speedway meetings.

a bit of info from ngk web site.

zgr6b-11 plug is
z= extended gap
g=14mm thread x 19mm long with 20.8 hex
r=resistor
6= heat range
b=suffix code?
11= 1.1mm gap..

the pgr6?
p=platinum
g=14mm thread x 19mm long with 20.8 hex
r=resistor
6=heat range..
now depending on the rest of the numbers, its pretty much the same plug but platinum.

another thought, what leads are you running?
I was running spiral core leads on my turbo 6 and at one stage was suffering spark blow out, my tuner pointed out that I was running a resistor plug with resistance leads and recommended I go with non resistor plugs to give better spark and put less load on ignition system..

Interesting info thanks Troyman. NGK told me it was a European Listing Number and couldn't be found on a shelf in Oz. The boys at my local Repco just gave me blank stares when I ordered them lol.

Running Splitfire Leads. Not sure if they are Resistor type or not. Just know that the Driver was very happy with the on track performance increase. That was backed up by lower lap times (plus I've used them in other Class's with good results).

But am always happy to try other things especially as this is my first foray into a Ford.

Our Engine Builder checked our exhaust as it broke at the last meeting. He said it was heavily sooted and declared it stuffed. He's proposed a slightly longer one so that the Torque Curve hangs on a bit longer - we will see. Exhaust's in this Class are a bit of a mystery. We have to run std Exhaust Cast Manifold but the Pipe is open once it draws level with the Fire wall. Any suggestions? Currently we run 2 1/2" non mandrel bends with the pipe going straight through a hollowed out Cat. Have to run a stock appearing Cat. The Pipe stops just before the Diff.

I'm sneaking the car off to my favourite Dyno before the Oz Title in Feb.

what is the part number of the splitfire leads.? im running splitfire plugs, when i ran back to back on the dyno it gained 9 rwkw

Sorry I didn't record the Leads part #. But if you contact Lynx Corporation Sales in Sydney they will help you out. I think it was Wendy that handled my Order. Leads arrived by Express Post next day.

Those NGK Plugs are going back. They arrived and the guy at Repco said that will $379 thanks - like hell it will!

This Team will be going with Splitfire Plugs as I've used them before and got really good Hp returns atrw with them. With a 208 Holden we found 2.6hp per cylinder. The Dyno Chap was impressed........

I also ran SF plug in a single cylinder Yamaha 490 (Formula 500 Speedway) and found a handy Lap Time improvement.

do you know which part number you are after? because im finding it hard to find them now as they stopped making the classic splitfire v's