Plug gap with Paxton and MSD
#1
Junior Member
Thread Starter
Join Date: Jul 2002
Location: Beaufort,N.C. near the coast
Posts: 92
Likes: 0
Received 0 Likes
on
0 Posts
Car: 92 Z28 Camaro
Engine: 350 TPI : Supercharged
Transmission: TH700R4
Plug gap with Paxton and MSD
What plugs and gaps are you guys running with superchargers and MSD ignitions? I have just installed an MSD 6AL ignition on my TPI 350 with Paxton sn 2000, and still have my plugs gapped at .035". The MSD instructions say to raise the gap to .050-.060, but should I try something different for a blown application? Thanks for any help.
#4
Junior Member
Thread Starter
Join Date: Jul 2002
Location: Beaufort,N.C. near the coast
Posts: 92
Likes: 0
Received 0 Likes
on
0 Posts
Car: 92 Z28 Camaro
Engine: 350 TPI : Supercharged
Transmission: TH700R4
Thanks for the info. Antoine, are you using the Paxton supplied air filter on your set-up? I hate the one that came with the kit. It seems way too small and probably quiets the whining sound down being it is made of paper. I would like to hear it whine a bit, and am thinking of going to a large K&N type filter. Any thoughts on this?
#5
Supporter/Moderator
I've got mine gapped to .035 now with the Accel 300+. Before w/ the stock HEI the spark was getting blown out at 3k rpms @ .045 gap (but 17 psi), and then re-gapped down to .035 & made it up to 3800 rpms.
#6
Senior Member
Join Date: Mar 2003
Location: vacaville,ca
Posts: 847
Likes: 0
Received 3 Likes
on
3 Posts
Car: 1988 camaro z28,1997 camaro lt1
Engine: 355 afr 195 heads,tpis big mouth
Transmission: 700r-4 built by me 3-4 z pack
Axle/Gears: 3.42
i put a k&n filter on it because paxton sends with the kit was a paper filter and they wanted 50 dollars for it put a k&n on it 3inch inlet.also i use ngk sparkplugs.
#7
Supreme Member
Join Date: Jan 2002
Location: Bloomingdale,IL
Posts: 1,322
Likes: 0
Received 1 Like
on
1 Post
Car: 91 RS
Engine: 305 Tbi (L03)
Transmission: 700r4
Due to the superchagers heat you will want to decrease the gap from manufacturers spec to reduse detonation. The specs just above stock are a great place to start. Youll also want to take the advice given above and use colder plugs. What you want to do is try different gaps for a few thousand miles and when you get the best fuel economy youll also be making the most power.
Trending Topics
#8
Supporter/Moderator
The plug gap has nothing to do with detonation. It's strictly the ability of the ignition system to generate a spark. If the gap is too large, you'll get a misfire (not detonation) since the mixture isn't ignited. Increasing the cylinder pressure (with boost or compression) creates a larger resistance in the air gap between the plug electrode and ground strap. Increasing resistance (with pressure or gap) increases the voltage required to generate a spark. When you don't have enough voltage, you don't get a reliable spark (i.e. me, at 3800 rpms on the stock HEI, .034 gap, and 17 psi) and get a misfire. You can close the gap, increase voltage (aftermarket ignition), or lower cylinder pressure to get the spark.
I just wanted to clear that up.
A.
I just wanted to clear that up.
A.
#10
Supreme Member
iTrader: (2)
Originally posted by askulte
The plug gap has nothing to do with detonation. It's strictly the ability of the ignition system to generate a spark. If the gap is too large, you'll get a misfire (not detonation) since the mixture isn't ignited. Increasing the cylinder pressure (with boost or compression) creates a larger resistance in the air gap between the plug electrode and ground strap. Increasing resistance (with pressure or gap) increases the voltage required to generate a spark. When you don't have enough voltage, you don't get a reliable spark (i.e. me, at 3800 rpms on the stock HEI, .034 gap, and 17 psi) and get a misfire. You can close the gap, increase voltage (aftermarket ignition), or lower cylinder pressure to get the spark.
The plug gap has nothing to do with detonation. It's strictly the ability of the ignition system to generate a spark. If the gap is too large, you'll get a misfire (not detonation) since the mixture isn't ignited. Increasing the cylinder pressure (with boost or compression) creates a larger resistance in the air gap between the plug electrode and ground strap. Increasing resistance (with pressure or gap) increases the voltage required to generate a spark. When you don't have enough voltage, you don't get a reliable spark (i.e. me, at 3800 rpms on the stock HEI, .034 gap, and 17 psi) and get a misfire. You can close the gap, increase voltage (aftermarket ignition), or lower cylinder pressure to get the spark.
I’ve messed with cars that have had to run gaps as small as in the low .02x” range to consistently fire at high rpms, but at that point you start getting misses at idle.
FWIW, gap does have something to do with detonation, but not what you expect. As the gap gets smaller the plug runs hotter and is more prone to becoming a source for preignition.
#11
Supporter/Moderator
FWIW, gap does have something to do with detonation, but not what you expect. As the gap gets smaller the plug runs hotter and is more prone to becoming a source for preignition.
Thread
Thread Starter
Forum
Replies
Last Post
Hotrodboba400
Firebirds for Sale
3
12-10-2019 07:07 PM
86CamaroDan
Engine/Drivetrain/Suspension Parts for Sale
2
09-29-2015 10:08 PM
89 formula TPI
Tech / General Engine
10
09-07-2015 11:06 AM