I've done a ot of reading/research as far as SC.Still have many questions.
Let me start of by saying I got a 90 Formula WS6,305 TPI/5 speed, mint in,out and under.I got the car for $2000 at a dealers auction and it already had dual-cat,3" flowmaster set-up.104K(now 120K)I did the usual mods:full Accel ignition upgrade,K&N filter, air foil, TB coolant by-pass and Hypertech Thermomaster chip (I know I'll need a custom one for SC) w/stat and fan switch.
BTW I know some people here don't like Hypertech but I felt an incredible power gain from it. Before the car would not rev past 4,000RPM now goes past 5K.
Anyway here are my questions:
1. Since I got the bird cheap, I wanna keep this as much of a "poor man's porche" as possible. I noticed that things are always cheaper from re-sellers/dealers than from the actual manufacturer, ie Vortec, Procharger.
From what I read those are the best you can get. Which site sells those the cheapest?
2. I don't wanna get an Intake:TB, runners,porting ect,cam, heads, and Exhaust: Headers
upgrade just yet.
My question is if I get a perticular SC, can I add those things later or is each SC designed for a perticular engine-mod type? I realize about the chip upgrade thing.
3. What kind of PSI numbers should I get for a stock TPI-305?
4. What is the comp. ratio for my pistons? 9.5:1?
I drive this car 20-80 miles a week so it's not my pimary ride although I want it streetable.MPG is not an issue.
I'm gonna take it to English Town this spring to see what it does stock and later with the SC. I will of course post the results here.
I would greatly appreciate any and all help. If anyone has a same car as mine and did this. Great! If you are just knowlegable about this stuff, as many folks here are, please respond in great detail.
thanks
Mike
MZavrazhin@webtv.net

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90 Formula-WS6-TPI-305/5 speed. Slightly worked.

 

Mike,
You can put a kit from either ATI or Vortech on without a problem. Both run around 6psi. You can upgrade pullies with either one but that would increase the risk of leaning out or breaking a piston under boost.

Another thing you mentioned was that you have a hypertech PROM. You DO NOT want to use that with a supercharger. They increase timing which is what you dont want with a supercharger. If you put your stock one back in, that will be perfectly fine.

As far as compression, stock compression on your car is 9.5:1.

If you upgrade your heads/intake/cam later it will work just fine with the blower provided you select the proper parts. camshafts are really critical when you are supercharging as the wrong one will decrease your power.

Anything else, post here.
Good luck

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-86 IROC
Vortech stuffed EFI 406 in progress
-=ICON Motorsports=-

 

Thanks for the info,Guido.
What I wanna know is where do I go for the best price on the blower?Which website?
Thanks in advance.
Mike

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90 Formula-WS6-TPI-305/5 speed. Slightly worked.

 

Normally I agree with Guido on supercharging issues, but not on the aftermarket PROM issue. Aftermarket PROMs incorporate a more aggressive timing curve than the stock unit, which is a good thing on a naturally aspirated engine.

The "normal" line of thinking:
Any time air pressure is increased, heat is generated. An aftermarket PROM which incorporates an agressive timing curve should not be used on a supercharged engine because it can cause detonation, which is a killer. So the PROM should be burned with less total timing.

I was also a victim of this line of thinking at one time. My TPIS Level V PROM was burned with a total timing of only 30 degrees. Perfect for a supercharged engine.... Makes sense, right? Read on.

My line of thinking:
If you can significantly reduce the inlet air temperature, detonation would not occur. This is where the theory of intercoolers and water injection enters. Both effectively reduce air temps to the point where timing does not have to be retarded.

I have run water injection in the past with great success. This coming year, I will be running both an intercooler and water injection. I had my PROM reprogrammed with a very aggressive timing curve. What a difference. My signature shows my results. In addition, I suggest using an adjustable timing module in addition to your aftermarket PROM to "fine" tune for varying track and weather conditions. I have one and love it.

Read my article on coolant fans in the tech article section. It should give you some ideas on how to optimize your coolant/fan systems.

I ordered my D1SC from David Back at Tenacious Performance. E-mail him at dback@tenperf.com for a quote. I could not find one cheaper. However, Dave does not sell Vortech, only ATI. You might want to ask him why.

Yes. However, with increased intake flow, boost will decrease. This is not necessarily a bad thing. Recall that boost is resistance to flow. If you increase flow (thereby decreasing boost), you should not see a performance decrease, only increased efficiency. I experienced this phenomenon first handed. I was running 10.5 psig with stock heads and cam. With the same compressor, my boost decreased to 6 psig with the Crane 2032 cam and Corvette aluminum heads with 8.8:1 compression ratio. Trial runs at the track with and without the supercharger yielded the same improvement, before and after the cam/head swap.

I also calculated V.E. (volumetric efficiency) on one of my runs at the track given values I scanned with my Auto Xray. My V.E. is 139 percent. A V.E. of over 100 percent can only be achieved with a supercharger, turbo or nitrous. Given that an optimized (modded) normally aspirated engine achieves about 85 percent V.E. and back calculating, my supercharged 305 is equivalent to a normally aspirated 431 cubic inch engine.

The boost figures from Vortech and ATI are based on a stock engine. So if you install a 9 psig kit, that's what you'll get. On a modified engine, it's a crap shoot -- trial and error.

Stock compression ratio on a 305 TPI is 9.3:1.

I drive mine on a daily basis (about 150-200 miles per week), it's totally streetable and emissions-legal. I even use it for business.

A note on blower cam selection:
When selecting a cam, do not discount one solely on it's advertised lobe separation angle. Just this spec can be misleading. Find out the valve timing specs before discounting a cam. My cam is a perfect example. It is a Crane 2032 with a 112 LSA. Generally, a blower cam will have a 114 LSA or greater, which minimizes valve overlap which is a bad thing on supercharged engines. But if you inspect the valve timing events on my cam, it has absolutely no overlap -- and it has a 112 LSA -- perfect for a blown application. Hope all this helps.

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Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
12.57 @ 111 mph.
12.04 @ 114 mph (50-hp nitrous).
http://members.optushome.com/au/downunder1/rides/willie/willie.html

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

My custom front marker lamp assemblies:
http://members.optushome.com/au/downunder1/misc/lens.html

[This message has been edited by Willie (edited December 24, 2000).]

 

Thank you very much. Got more answers this time around.BTW I read your other articles before I posted here. Very inormative. I learned a lot.

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90 Formula-WS6-TPI-305/5 speed. Slightly worked.