Some suggestions for a mildly modified L67
 

Hey guys, I finally found and purchased a 99 Regal GS Black with gray leather interior, moonroof, heated seats etc. and 65k on the clock. I know it's not a Bonnie, but the guys on this board were very helpful while I was searching for an l67 powered car, that i wanted to post here to get all of your opinions on some simple mods. Here's what I want to do over time:

1. 180 T-stat (already done)
2. Custom Fenderwell Intake
3. U-bend & resonator delete
4. 2.5" exhaust, possibly with aftermarket muffler or possibly the SLP cat back.
5. 3.4" pulley
6.TB spacer and heat shield
7. one or two step colder plugs.
8. tranny cooler (not sure on this one)

My questions are.
1. for the mods I plan on making would I need 2 step colder plugs or would one step colder plugs be fine.
2. for plugs shoudl I go with Autolite or NGK V-powers?
3. To add a tranny cooler or not? I've read on a few sites (ZZP & Intense) that this mod is un-necessary?
4. any other mods you'd suggest or possibly any mods I've listed that you would not suggest?

Thanks for you help.

First of all, it might not be a Bonnie, but you're more than welcome here ;)

1. For those mods, you might not even want one step colder. Stock plugs will be fine, but definitely not 2 steps until you have a smaller supercharger pulley. The size of that pulley may determine which heatrange (one or two) colder you go.

2. I personally don't like Autolite, but honestly haven't run them in over 20 years. I'm a huge fan of NGK, and GM is too. The AC Delco plugs are made by NGK. I run the V-Power TR6, 2 heatranges colder. You would probably start with the TR55. One heatrange colder.

3. Tranny cooler? Heat is the enemy. For the lifetime of the trans, I suggest it. Performance wise, it really won't add anything, but for lifetime, it will help. It won't prevent you from blowing the diff or a gear, but it will extend the life of the fluid, pump, friction bands, etc.

4. Pulley for sure after your intake and exhaust. That's a huge mod to move up the list for sure.

Godd luck!

Oh Damn, I can't believe I forgot to mention the most important mod. :doh: yes the 3.4" pulley should be number 5, right after the intake, & exhaust. :lol:

2 heatranges colder ;)

Re: Some suggestions for a mildly modified L67
 

1 step is fine after you change the pulley, not before.

Either is fine, i prefer autolite (605 is 1 range cooler) as they are cheap and copper (you NEVER want to use a platinum plug in an L67).

The tranny fluid is cooled by the radiator and its heat is controlled by the thermostat for the coolant. If you go to a 180 t-stat you will effectivly be cooling the tranny fluid at 180 as well. No point in introducing another point of failure by adding a tranny cooler unless you live in a hilly area or plan on hauling things with it.

Once you are done with the above, then 1.9 rockers and a PCM and your car will be smokin! :)

maybe do the U-bend delete earlier. Its cheap, easy and good for like 5 hp/tq.

Re: Some suggestions for a mildly modified L67
 

Basically what he said is great. A tranny cooler is one of the most overrated things available for these cars. There is a factory tranny cooler in the radiator, and that should cool the tranny as much as you could ever need for normal driving situtaionts. Unless you drive in a VERY hilly area and/or tow a trailer or you autocross the car or something, I can't see you ever needing it. And what some people don't ever say is a tranny cooler can cause the tranny to run TOO cold and that can cause it to fail just as easily as it getting too hot.

For spark plugs I would definately not go more than 1.5 heat ranges colder, I would probably stick with 1 range colder. We ran 1.5 range colder platinum plugs in the GTP up until it ran 12.59...and that was with a 2.6" pulley. :roll: Although I can't see platinum plugs hurting it at all, the factory plugs are platinum plugs, so were the plugs we ran in the GTP up to the 12.59 and the ones that are currently in the SSEi are platinum. They may run a LITTLE hotter than copper ones but the fact that they last 10X longer is worth using them IMO. The only time I wouldn't use them is if you are using nitrous or you are trying to squeeze every little bit of performance out of the car as you can.

Shawn

Thanks for the input, Rogue and Shawn. Keep in mind that I live in a fairly mountainous area, and tow a trailer occasionally. I agree with the 'too cold' sometimes. I'll be switching to a thermostat-controlled trans cooler soon, to replace both the factory external cooler and the aftermarket cooler. I do find it interesting that the SSE and SSEi for Series 1 got an external (additional) factory trans cooler.

As far as plugs are concerned, there's good advice here. Finding the transition from one to two heat ranges colder can be tough. I went through two sets of TR55's before I decided to go to the TR6. Good move on my part. I assume I'm just over the threshold, but remember that when I hit 12psi, it's producing alot more heat than a Series 2 with a 3.4 pulley.

I drive an old dog, but drive it hard ;)

thanks guys, keep the replies coming. Once again this site is providing me with some very helpful information.

Here are some pics of my new girl, http://www.cardomain.com/id/thunder87