99TransAmDude

I'd like to put a review of the LS3 style VMS ignition coils I bought since I couldn't find a single review online for any type of car before I bought them. The mods on my 99 Trans Am before the coils were Edlebrock headers, GMMG catback, ported MAF, K&N, so nothing crazy.

I installed a lot of products at once. I switched to the Holley LS valve covers so I wanted to go with red LS3 coils. MSD coils were a bit pricey so I opted for VMS which I never heard of. They were only $215 with free shipping on Ebay.

Now if I were smart, I would've installed the coils first and test drove the car. It would've been much easier to troubleshoot. I'm not a mechanic but I have 20 years of working on my cars in my garage from brake changes to engine rebuilds.

I installed a FAST 92mm Intake with Nick Williams Throttle body, LS6 Valley pan with the new built in PVC, Holley LS valve covers and the VMS LS3 coils which required new wiring harnesses to convert to the new style plug. I also replaced both knock sensors and the harness (wow was the stock harness boot worn out. They were like hard plastic).

I took my car out for a test drive and it drove like crap. Had no power, shaky acceleration and idle, and popped between shifts (mainly 1-2). I did the usual tests. I checked for vacuum leaks, etc. My Aeroforce Interceptor OBD2 gauge was showing zero misfires and zero knock retard. No check engine light either.

After a week I brought my car to Straightline Performance. They're awesome. Very friendly and they're the only ones I trust to work on my car. I figured maybe it just needed a tune. They hooked it up and couldn't even complete a run. It wouldn't get past 220hp then it would really load up. Their scan showed a problem with cylinder #1. It was sparking but just barely (why I read zero misfires). They swapped coils with #3 and the problem moved to #3. They had an extra stock ls3 coil laying around so they plugged it in to complete the tune.

I had a replacement VMS coil sent over from the ebay seller and in the meantime I put in brand new bosch platinum +4 plugs and msd wires and when I drove my car, it ran better but was still popping between shifts and still had poor power. What the hell......

I had enough and ordered a set of MSD blaster coils. My car ran flawless.

In the end, the MSD coils only cost $130 more than the VMS coils. After $450 for troubleshooting and a dyno tune, I wish I would've ordered the MSD coils in the beginning. It would've saved me $320 (although I might still have needed a tune with the new intake). I guess it pays to buy name brand stuff.

Exidous

iTrader: (11)

Any airflow or fuel mods will call for a tune but you're right. There are some things you can use china parts on and some you just cannot. I guess coils are one of the cannot.

Thanks for being the guinea pig at least. :-)

96capricemgr

iTrader: (1)

You need to try to understand things before you make more mistakes.
Spark mods were a really poor idea, the bosch plugs as bad as the shiny red coils.
Ported MAF without tuning tables for it just ruined the calibration and at your level pointless even with new calibration.
YOU are making poor mod choices, then buying bad parts to complete those bad mod choices.

99TransAmDude

I forgot to mention, I had a new tuning calibration with my original ported MAF so that part wasn’t an issue. I wanted a black MAF and they all come ported.

I have to disagree with some of your statements. I have a couple relatives that work at Bosch and in my opinion, they make outstanding products. Plus I couldn’t see putting the $1.25 ac Delco plugs in since 4th gens are difficult to get to the rear plugs. I know there is no power increase or anything like that from spark plugs but the Bosch platinum +4 have four contact points so there’s less chance of the gap changing over time on all of them.

I wasn’t after huge power increases. I do a ton of car shows…racing isn’t my thing. Around the Chicago area, cruise nights are insane. I have the choice of probably 4 different cruise nights every day of the week in the summer and fall. It would’ve cost me even less to do a cam swap and I would’ve gotten more power but you can’t “see” a cam at a show. The black/red fast intake with throttle body, black ported maf, holley ls valve covers and the red msd coils look awesome. I thought of just getting AC Delco OEM coils and painting them red but that would probably look bad since I can’t paint. Plus I’ve read countless article of a ported MAF picking up about 3hp (3hp who cares, but like I said I wanted a black one and they're all ported) and the intake/tb combo picking up around 18hp over my stock LS1 parts at my car modification level. I did it mainly for looks but if I pick up a few hp, that’s cool too.

I think the only poor choices I made were buying the VMS coils and not MSD coils and not test driving my car before continuing with the rest of the mods.

stevieturbo

Bosch do make good product...but I'd always choose NGK or Denso over Bosch.

And unless someone can show good reason to use anything other than genuine GM coils....just stick with them

99TransAmDude

I agree, the stock coils are the best to go with but my swap was purely for looks. I was just hoping for something that actually works...lol. My car is driven less than 1000 miles a year so longevity and performance aren't as important.