The MSD withstands 6500+ rpm's, OEM does not. (for long atleast) I couldnt make more than 5k miles out of my OEM opti's MSD has held up good so far.

 

It's comforting to hear that some people are having positive experiences with the MSD.

 

The MSD unit is a better made peice. It seems Accel is junk. I don't want to buy one from GM because I think when GM called it an opti-spark, they don't mean optical sensor, that is just a cover, but in reality it is optimal profit. Gm had been using DIS long before the opti was even tought of.

 

Well there is one more option,the dynaspark.It is expensive and not to popular on here but when my opti went bad at a mere 9000 miles,and that is in good weather only,never driven in the rain and no water pump leaks.I decided the oem just would not do,i thought about MSD but after doing alot of research i decided on the dynaspark.Now after getting it i have to say it really looks like a quality peice.I have only had it for one summer so i can't swear by it but the car works better than ever with it on and there are guys on the corvette website that have had it for 2 and 3 years and have never had a problem.I went there and found very little negative and alot of positive things said about it by those guys and that is why i got it and so far i am very pleased with it.Just something for you to check out.

 

Ive had the MSD opti since it first came out. I haven't had any problems with it and its been nearly a year and about 12000 miles, highway mostly. I did remove it a month ago due to the timming chain cover leaking. I did notice a very small amount of dried oil in the opti. Doesn't affect it at all though cause it still ran like a champ until I blew up the engine.

 

For 500 why not spend the extra couple hundred and get ltcc and coils!

 

I have about 13,000 miles on my MSD opti and I was one of those who had a problem with early on. After MSD rebuilt it, it has been working great. If you have a nonvented Opti, the MSD comes with a venting kit to convert yours alot cheaper than upgrading with OEM parts.

I personally think the MSD is the way to go because the design seems much better to me. Of course only time will tell if they are actually better.

 

I could be putting my stupidity on display, but does the vacuum harness that MSD supplies with their 93-94 opti replacements come with flow restrictors or are they even necessary with their setup? Do they have you make vacuum connections in the same places they would be with later model vented OEM units?

 

THere are vacuum restrictors and I am not familiar enough with the plumbing on the later models to say if it is the same. ONe tube goes into the intake elbow on the passenger side just before the throttle body. The other one T's into the vacuum line next to the brake vacuum boost hose on the intake manifold.

Jeff

 

Those are the stock locations. Does the 93-94 intake have one of those vacuum holes plugged or just no hole? I have one for the EGR and one for the opti and then another big one for the brake booster.

 

Thanks for the info SweetZ!

 

Wolf, If you're talking about the connection on the elbow, I'm pretty sure that my 94 intake just doesn't have a hole. I believe the MSD requires that you make your own hole in the intake.

 

No, I meant on the engine intake, not the elbow. I know that the elbow doesn't have a hole.

 

Sorry for the delay. I have been having problems in accessing email. THe 94 just doesn't have a hole. You have to drill one in the elbow and the kit includes the T and short piece of hose for the intake connection. You just pull off the exisiting hose and insert the T in line. The MSD is expensive but I do like the design. Last week my motor went (cam shaft lobes on #1 cylinder worn out) so I pulled the motor (323,000 miles). I am going to open up the MSD and take pictures of the inside for everyone to see how it is holding up. I'll post soon.

 

The holes on the drivers side of the intake manifold are the same for all years. In the 93/94 cars, the lower/rear port is used for the PCV valve vacuum, connected by a short U-shaped hose. In the 95-97 cars, the vacuum for the PCV valve is run from a small port on the front of the manifold, under the throttle body. That frees up the lower/rear port on the side of the manifold for the Opti vent vacuum line. The port under the throttle body is there on the 94's as well, but it has a pipe plug in it. (Don't know if they had it on the 93's).

95-97 from Shoebox:
http://shbox.com/1/opti_vacuum_conn.jpg