I just switched from TR6s gapped at .036 for nitrous use to TR55 at .055. Man you can feel a difference, before I swapped the plugs the car felt fast. After I swapped the plugs you could tell a noticable difference in throttle response and it felt faster on the top end. Could this be just a mind thing?
Phillip :eek:

 

Maybe it is a mind thing. Are you not going to run NOS anymore? Is it ok to run those plugs with NOS? Are you building a S/C for your car, or turbo?

vetterdstr :cheers:

 

It's not in your mind. I have seen many on LS1tech.com switch over from their TR6 to TR55s and pick up 10-15RWHP and decreasing their E.T.s and gaining MPH. (These are all N/A runs never spray N20 with TR55s)

 

Umm....9.0:1 cr....15psi...T72.....111 unleaded gas :lol:
Phillip

 

Buckmaster, it does make a difference when switching to plugs of different heat ranges. The TR6s are much colder than stock so this gives a cooler and slower burn in the combustion chamber which can rob power. Switching to the stock/proper heat range provides for a much hotter and quicker burn = restoration of power ;)

 

The hotter plug coupled with a much larger gap will probably make more horsepower. I am going to dyno to see the difference.
Phillip

 

hmmm... please post the results..

 

I find this hard to believe.....anyone who gets that kind of gains by switching plugs either had a bad plug to begin with or has an extremely modded motor (very high compression, blown, etc) that is very sensitive to plug changes......

 

see sig....11.75:1 burning 111 unleaded race gas isnt stock. :lol:
Phillip

 

Agree with Oliver

 

On a side note this is the same setup that I put 545/620 down on the dyno do I dont think the plugs are bad.
Phillip

 

Oliver, I can't find those two friggin' posts I read that on LS1Tech, I have been searching for 30 minutes and can't find the darn things. Oh well. I don't believe that everyone would gain much from this switch however there are circumstances that would make a hotter plug more beneficial for N/A use.

i.e. Say someone has a stock CID forged motor yet sprays a monster shot (150+) with their TR6s. They will already have a really small gap and a colder heat range plug during N/A use. As described above, a small gap and colder plug = less heat during combustion and a slower burn = loss of N/A power. A bigger gap and hotter burning plug in the same motor N/A will provide a much hotter combustion action (more driving force down on the piston) and a quicker burn (only helps accelerate the piston more) thus more power. I mentioned the gain of power I have read before on this issue b/c Phil ain't stock and sprays a big shot too so it may be relevant to his case ;)

:cheers:

 

The reason why spark plugs are available in various heat ranges is to control the temperature of the firing end of the spark plug. Too high a temperature and you get pre-ignition. Too low a temperature results in fouling.

The insulator nose length, gas volume around the insulator nose and the materials/construction of the center electrode and porcelain insulator are the factors that influence a plug’s ability to dissipate heat or its heat range.

No matter what kind of engine you’re talking about, be it a lawnmower, grandma’s Buick, Phillip’s Vette, or a formula one car the spark plug temperature must remain between 500C-850C. If it’s below 500C, the insulator area around the center electrode will not be hot enough to burn off carbon and combustion chamber deposits. If it’s over 850C, the spark plug will overheat which may cause the ceramic around the center electrode to blister and the electrodes to melt. This may lead to pre-ignition/detonation.

When a spark plug is operating in the desired 500C-850C temperature range, the plug firing tip has neither carbon and combustion chamber deposits nor a white, blistered appearance. Instead it looks clean with a light gray or tan color to the insulator.

Changes in A/F ratios, compression, camshaft, timing, engine speed and load, air temperature, humidity and barometric pressure are external factors that affect spark plug tip temperature.

You don’t need a dyno to determine the proper heat range; you just need to read your plugs.

 

Good point SFVetteman.

To expand a little.

Gapping a plug is important too.

You want the largest gap you can get, so that you cam maximize the efficiency of burning the entire mixture. Increasing gap is dependent on the power of the coils, and the enviroment of the combustion chamber.

When you increase power, be it from more compression, better flow, forced induction, etc, you want to begin lowering the gap, because the spark will literally be blown out before its effective. You can counter the need to narrow the gap by adding a more aggressive ignition system (coils etc).

Its a balancing act.

 

I dynoed at 354 rwhp stock, 374 rwhp with minor bolt-ons, and now have to re-dyno after I installed my FLPs. I have two questions: 1) can you squeeze 50 or 100hp with the TR55s?, and 2) does anyone know the formula for plug gap reduction, i.e. for a certain number of increased horsepower, you should reduce your gap by a certain amount to compensate for the additional air that is being introduced into your combustion chamber?

 

I know it is purely non-scientific, SOTP gut feel, but my car seemed smoother at idle and stronger when I got on it just going from the stock plugs to TR55's. I am getting LS1-Edit (and obviously multiple dyno's) tomorrow, so I'll be curious to see what she's putting out. I'm not in the same HP league as most of you in this thread...just Blackwing and Corsa's here.

 

In general, you reduce gap about .004" for every 50 hp you add on an V-8 engine.

 

Shawn - what is the stock gap on 02 Z plugs? I never checked my OEMs before I threw them out for a set of Tr55s... :seeya

 

Brent, according to the 2002 service manual its .060 for LS1 and LS6 engines.

The C5 ignition and coils are very efficient and strong, and probably doesnt warrant much need for a gap decrease with the HP differences of the LS1 and LS6.


[Modified by kewlbrz, 11:01 PM 12/4/2002]

 

So, if after the FLP w/no cats install and after I have my PCM reprogrammed by Cartek, I am making in the neighborhood of 400 rwhp, I should go with the TR55s gapped at .55?