I know there is a topic about a 3.3" pulley (series II), But the series I has a smaller pulley stock; so I will pose a similar question.

The stock pulley on the 95 L67 is 3.0". I have a 2.7 incher on it with my CAI, 180 Stat, and 50K since tuneup. It seems to run good, but I was wondering if I should change to colder plugs, ect. I realy need a boost gauge on it. The car does not run hot and I don't HEAR pinging. BTW it also has the BCS mod as well.

What do you all think, I am I safe?

BCS mod does nothing but get you into boost quicker. It doesn't add boost.

Your stock pulley was 2.8". A mild step to 2.7 would have very little effect. maybe 10hp and 20ft/lbs of torque. I think stock plugs would be fine for that.

Get a scantool and a boost gauge. You need both if you're going to go smaller on the pulley. 2.5 is generally safe for yours, but you never know unless you scan.

I'm moving your post to Forced Induction.

Yea, you must be right, when I got the pulley from pulleyboys, it seemed very similar in size to the old one and I did'nt notice a huge difference. :? However, the BCS mod seemed to "fix" somthing as I had a fraction of the power before. I suspect the Quad driver one error was partly to blame.

What can I expect with a 2.5 incher?

I will get a boost gauge and scantool soon. In the mean time I will check a few plugs to see how they are doing.

2.5" will net you 25hp and 40 ft/lbs. That'* the step most of us take. But it takes a very well-tuned car and a sharp eye to manage it. At times, I can get 10 degrees of KR on my 93 with a 2.2" pulley (stepped down from a 2.5 stock). In extreme conditions, It'* a battle to manage it, so I've recently made several changes to the top end of the motor.

wow, that is disapointing to hear. I suppose the inefficiency of the eaton is to blame. I will likely keep it the way it is and go turbo in the future. Its hard to beat 70% compressor efficiency with a turbo where the Eaton is in the 55% rating.

The Eaton is a helluva lot more efficient than that, and you have boost immediately. No lag. That equates to low-end torque, and you'll lose it going Turbo.

For the record, most Eaton SC'* are pushing 90% VE.

But unfortunately, it'* still a big hair dryer.

Is VE the same as thermal efficiency?? From what I know the Lyschom screw chargers are very efficeint thermally where the eaton with the rotors is not.


This website explains the pros and cons of the two very well. I am wanting to run higher boost pressures, therefore a turbo would be a better choice for me.

http://www.automotivearticles.com/Su...Choices_.shtml