I have a 2000 C5 (450HPapprox)with a vortech supercharger and exhaust. I was wondering if anyone has upgraded there ignition to a MSD system(coil packs). What kind of HP gain would i get from this? Would there be any side affects i should know about? Would it be better to spend my money somewhere else like a blower cam or heads? My goal for next year is to have my car running low 11's so any suggestions would be great. Thanks for helping out a new guy.

 

Unless you have some reason to think that the ignition is limited power leave it alone. I've still using my original coil packs at 700+ RWHP and they do fine.

You did not mention if you are at 450 RWHP or just an estimated 450 HP flywheel (would measure about 405 at the flywheel).

You did not mention any other mods you have but I assume you have long tube headers, etc.-- would be sort of non-optimal to install a supercharger and not have those. So, unless you have your Vortec maxed out, the easiest and cheapest way to get more power is to just increase boost by fitting a smaller pulley. Standard Procharger or Votex models can blow enough air to out a C5 into the 520+ RWHP range: it might take upgraded injectors, an eight ribbed belt set, etc. But its still pretty cheap compared to other options.

One thing to think about is that 450 RWHP is not far from where stock short blocks start to give real problems: go much over475-480 RWHPand the motor will come apart on you, maybe not tomorrow but within a few thousand miles. I have never seen a C5 with the stock bottom end on the engine do low 11s and survive long. My advice for getting to the low 11s would be to buy a good built short block with heavy duty components, might as well get a stroker while you are at it: it costs almost nothing more. A 383 with an Eagle crank, etc., and 8 lbs boost ought to do the trick and survive to do it many other times, too.

 

Hi Lee. Your exactly the guy I wanted to talk to. I'm new to the Corvette world and to this forum and in the past two months I have learnt more than I thought was possible thanks to alot of your posts and the other techs on this forum.

First things first. I bought this 2000 c5 used at the end of last year. It had 20,000 miles on it and was in excellent shape. So there are some mysteries to the car because i'm the third owner. When i say "450hp" i ment RWHP. However i don't have any proof of this. I found a piece of paper in the glove box saying 450RWHP, Full corsa exhaust, 421 pound bosch injectors ( I think- hard to read), custom programming, and Vortec supercharger. I will dyno my car soon and upload it on the forum.

As to your suggestion, I beleive that is what i'm going to do. I don't want to blow this motor up. You mentioned in another post about SLP performance engine packages and I was wondering about ZL402 LS1 iron short block with low compression. I thought it would be a good combination for the blower but i'm not too sure about what kind of heads, boost, and cam i would use with it. I will also leave my stock ingnition on too.

I have a 90mm FAST intake at home in a box so hopefully that will bolt up too. I also have on order a 6 point roll bar, 160 degree thermostat, Line lock,
high flow mass air flow sensor, and a DTE rear end brace. From the reading i've done it sounds like I will need hardened axels, and a stage 2 clutch like you do in your car. I would love to hear any other suggestions too.Thanks

 

My comments and answers, for what they are worth.

First, I'd get the car to a good shop (not the first you find necessarily, a good shop -- one that has a record of working on modded vettes andtuning them well) and have it dynoed and checked over pretty thoroughly. Find out what you have. If in doubt pay the price and have it tuned (custom programmed again) well. The car might have been mis-represented (not too likely from what you say), but: you don't know how good the custom programming was (often it is only so-so), and you have no idea what other aftermarket parts it has or does not have on it.
A key thing to do is find out what model Vortech you have and what size pulley it is running (say 3 1/2 inch) versus the smallest it can run (say 3 inch). Your shop can tell you what it is running now and give you an estimate of the smallest pulley it will run. If its running, say, a 3.5 inchbutcan run a 3 inch safely and efficiently, then you have about (3.5-3)/3= 16% capacity left. If its running a 4", though, you have 33% more capacity left. This is critical because you need to know if the thing can blow enough air to feed a good 402 or other stroker motor. A 402 is roughly 14% more displacement than a stock engine, one with opened up heads breathes about 20% better, etc.: no use going that route only to find your Scr can't keep up. Finally, a call to Vortech ought to verify everything and get their recommendations.
Similarly, ask the shop how much power your fuel pump and injectors will make before they must be replaced.
Then, you have two routes.
A) Quick: If you are impressed by the shop's work and trust them (not just trust them to be honest but trust them to really know what they are doing) you can tell them your goals, given them your budget (hold back 15%) ask them what they recommend, and let them do it. Generally this is the only way you will get good results quickly. Given you live in Alberta this means you might actually get to drive the modified car before winter close in.
B) Fun. you can do some research and develop a plan yourself. Call SLP and talk with them. Call other LS engine builders (Horsepower Engineering, MTI, Mallet, etc.) and find what's available. Get a copy of GM High Performance magazine and scour the ads, make calls, etc. There are lots of aftermarket short blocks and speed parts.
Most important, develop a plan for where you want to end up, a full descriptionof all the mods with some effort made to assure they work well together (i.e., if you install an aftermarket cam is it one that makes sense on a SC'd car). Work to your budget and don't overreach. Hold back about 15% for things that will surprise you (on my car, it was the rocker covers - stock ones, even extended, would not cover the new shaft-mounted rockers -- that cost $1500 to fix). Then order the parts and have the shop make the mods and do a good tune. Somewhere in there, install a good aftermarket expanded capacity radiator with an oil cooler, too. With the supercharger (at leastone with the capacity), don't spend too much on the heads or extreme valves or breathing -- you can use boost to force HP when you want it and you will actually get better around towon driving with them not opened up too far.
This route generally takes longer but is more fun if you are into re-engineering your car.

The FAST manifold will definately help. I'd probably leave it off until you put on a stroker. They are overkill and can cause driveability problems on stock engines. I assume you have a 90 mm throttle body for (can't use it without one (those cost more than the manifold itself). On some, your shop will want to do the "drill mod" which involves removing the butterfly and putting a 1/8 inch or 5/32 inch hold in it (otherwise you get a wavering of power low speed (35 mph) city driving).

 

Thanks for the reply Lee. I'm going to do just that. Take it to Wester's Garage for them to check it out because not knowing what's on your car can be little frustrating.I'm going to go through a detailed plan and do this over winter. I will also be purchasing a hoist so i can do a few of the mods myself (cage, rearend, etc) but i won't be doing the engine or tuning for that matter. I think the radiator and oil cooler is key too. I went through so much heat problems on my old volare road runner, but that was just the learning curve i guess. I'm glad you mentioned my blower because i just assumed it would automatically be able to push enough air into a 402 cid. So my gauge says 7.5psi when my foot is through the floor. Does this mean if i had a 3.5" pulley and I changed to a 3" that i would end up to 8.7 pounds boost?

 

hey lee, did you mean that the 90mmFAST intake isn't good on stock engine? what about the 75mm? i was planning on this being one of the first things to do, but what do i needbefore i put the FAST intake on? possibly LT headers, throttle body, replace the gooseneck air bridge? it has new exhaust and CAI. sorry to steal the thread, btw.

 

From what I have seen, the 90 mm is too big for a completely or nearly stock engine. the big channel crosssection means that bot air speed and turbulence at low RPM will decrease a lot and that will hurt low and mid range torque. At high RPM it won't do that much more than the 75 mm. When you consider the cost of the 90 mm throttle body, too, it is a rather expensive upgrade to make when there are other things (cam) that can do more first.