Does this really improve perfomance or HP?
http://www.madvet.com/shop?store=3&c...y=14&frame=824

Just looking for peoples opinions... especialy those who have one.

Thanks!

 

Not really. The coils GM used for HEI and on the LT1 are pretty powerful. I am getting ready to install an MSD coil on my LT1 along with the 6AL. It isn't really needed. From what I have been told about adding the 6AL on the LT1, I will gain a smoother rev from it. My coil is old anyway and want to replace it before it takes a dump on me. Since I am doing MSD wires and new plugs, I thought I would do a little modification to the ignition system so if I ever get the chance to supercharge it, I have the spark.
:cheers:

 

Careful with aftermarket high output coils on LT1's and LT4's. Can cause carbon tracking to start setting up inside the Optispark distributor.


[Modified by Lone Ranger, 2:18 PM 8/22/2003]

 

GM HEI coils are good for over 50kV open voltage. Their claims of over 40% increase over stock are bogus. I have checked their coils on an ignition scope and have never seen any such increases if any vs a standard GM coil. A 96 LT4 coil is one of the most powerful "street" compatible coils you will find anywhere.

When I say street, it means designed for continuous duty, a race only coil will put out more energy but it is designed so that it is only meant for intermittent duty. I have seen "kids" use these coils on their street cars thinking they will benfit from them, only to find themselves stranded on the side of the street wondering why their car stopped running!

As for installing a MSD 6AL on your Vette, if that is really what you want to do. I would suggest looking at Crane Cams ignition box. MSD old standby 6AL is a good box, but it is of a very old design and MSD hasn't updated the electronics design in a long time. Cranes box is has much more advanced circuitry design and is even more reliable than the MSD Box. Plus it uses weather pak connectors to make installation that much easier and more reliable. Depending on what year your car is and if you have a newer Vette that uses the remote HEI coil, I would just go to GM and buy a coil for a 96 LT4 Vette, then buy the MSD adapter harness to fit that coil and go with that. It would be cheaper than buying a MSD or a Crane coil and you will have a better installation in the end.

 

The stock HEI on L98s ran out of power much over 4k RPM, which was not much of a problem with shift points in the mid to high 4k rpm range.

The HyperTech setup stays flat much higher and puts out hotter spark. Combine that with a set of hi-performance wires and you can open the plug gap to .045"-.050" on a NA engine (I run about .047" gap). Then install cut-back plugs and you will get more complete combustion for a little power & economy gain.

I run the HyperTech coil/cap/rotor, TPIS wires and AC Delco cut back plugs with good success. I picked up 8-10hp and pull 32mpg highway with 2.59 gears.

So, I recommend the change from stock HEI, along with the other ignition upgrades if you want you L98 to fire reliably above 5k RPM.

 

Quote ---------------------------------------------------
can open the plug gap to .045"-.050" on a NA engine (I run about .047" gap). Then install cut-back plugs and you will get more complete combustion for a little power & economy gain.

I run the HyperTech coil/cap/rotor, TPIS wires and AC Delco cut back plugs with good success. I picked up 8-10hp and pull 32mpg highway with 2.59 gears.

So, I recommend the change from stock HEI, along with the other ignition upgrades if you want you L98 to fire reliably above 5k RPM.
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ok... all you just wrote is a bit much for my beginner brain :confused:

How do you open the plug gap to 0.45 0.50.... how much is a normal plug? what brand or type of plugs do you recommend for doing this?
what do you mean by NA engine?
how do you cut back plugs?

And is it hard to change the Coil to an after market one... do you have to readjust the timing?

 

No problem, life is a learning curve.

The stock gap on my '88 L98 is .035"; I use a spark plug gapping tool to bend the ground electrode open a bit. The advantage of this and cut-back plugs is to provide more flame front to the air/fuel charge to get more complete combustion.

How to cut-back the ground electrodes is described on my site; I chose stock AC Delco plugs available at most auto parts stores.

The HyperTech coil/cap/rotor comes as a package. You just remove the stock cap & rotor, replace with the new rotor and cap and you are done. The new coil is inside the cap so you don't have to deal with it separately.

It's not hard to change this setup but use a little Liquid Wrench on the dist cap hold down screws as they tend to rust underneath where the protrude below the dist base. When changing wires I like to label each end to be sure I don't corss any. Also it's easier to change wires when you change the cap.

Since the HyperTech cap is larger than the stock unit, I had to use a Dremel to enlarge the rectangular opening in the center of the ring that slides over the stock cap to hold the wires.

You don't need to advance the base timing beyond the stock value of 6deg BTDC, but I run 8deg to get the best ETs with my setup.

NA=Normally Aspirated, as opposed to use of NOS, turbo or super charging.

If you do this mod, take your time and enjoy working on your Vette.

 

ah! I remember you!

I've been on your web site plenty of times, cool web site, lots of info, I'm bookmarking it right now.

Thanks for the explanations.. hmmmm what does ET mean? I'm guessing Estimated time on the 1/4 mile.

Talking about learning curve... I've learned a lot recently and I'm currently reading a Chevy small blocks book written by David Vizard.... actually I read the basic "How to rebuilt a small block" now I'm reading "how to build max performance chevy small blocks on a budget"
Trying to learn the real important stuff right out of a book instead of just taking peoples.

I'm learning alright!
got to go, done work for today
Thanks for you help

 

Elapsed Time :yesnod: :cheers:

 

Those two books or Dave's are great, enjoy.