A Trim -SC question

[vuvman2]

Hi All!

I have Factory Five Racing Cobra that has a 91 fuel injected 5.0 bone stock engine. Car wet weighs 1,900.

I was thinking of buying the V1-SC A Trim Vortech supercharger and I had a few questions.

First, I must say, I don't want to spend a lot of money. That is why I am going with the A Trim.

Second, The car runs perfect right now with the stock 60,000 mile motor and I want to keep it reliable.

So, here are my questions:

1) With the A trim, do I need a better fuel pump or injectors?
2) Will I get the 70hp they say I will get?
3) Will I feel the 70hp?
4) How easy is the installation and how many hrs?
5) Will my car continue to run the same.
6) Is 60,000 miles too many for a supercharger?
7) Is the noise the V1-SC ATrim makes good or just
irritating.
8) Does the ATrim setup give you the 6psi boost they say it will and is it upgradable?

Thank you,

Curtis

[Mitch Peoples]

I haven't looked at an A-trim kit, so it would help to know what's included. Let's assume it has at least a fuel management unit.

1) the fuel management unit (if included) will restrict the return flow of the fuel to the tank under boost. This will make the 19lb injectors perform like larger injectors up to a point. If you have a standard Mustang type of gas tank, I'd up the in-tank fuel pump to a 255lph unit. This will meet your immediate needs.

2) all 5.0 motors and tune-ups are different. Only a dyno will let you know for sure.

3) you will feel the difference.

4) if your configuration is the same as a stock 89-93 5.0, it should be relatively easy. The bracketry will relocate the alternator and smog pump (if you have one) to allow fitment of the supercharger head unit. You will need to have access to fuel line disconnect tool if you are running stock type rails and fuel lines to install the fuel management unit. You will have to punch a hole into your oil pan for the blower lubrication, unless you use a standalone oiling system. Whatever you do, take your time.

5) I don't see why not. If you get into additional work, such as non-stock cam, bigger throttle body and mass air, you will experience the joys of trying to tune it like most of us have already been through :D

6) I went high 10's at 128 on a 98,000 junkyard motor with an S-trim. Stock roller motors are pretty tough.

7) the blower won't be as loud as a you think. Just a nice whine.

8) the boost level is relative to the amount of restriction you have on the intake side of the motor. You may very well see 6psi. Double check on the www.vortecheng.com site, but I believe the A-trim is upgradeable to a standard S-trim. I've been wrong before.

Good Luck!

[vuvman2]

Thanks for the info!!

Curtis

[91GTFiveO]

I've got the SC trim. Here's my take:

1. 19 lb injectors and supplied FMU are adequate for a relatively stock combo. If you up the boost any (by changing pullies) or do something like heads/cam/intake, you will need to up the injectors.

2. Yes however, as setup from the factory, the stock engine will run pig rich through the boost range. Recalibrating the FMU during dynotuning can net you 25+ hp.

3. You will definitely feel the 70+ hp. Especially with the flyweight car you have.

4. Installation will vary from person to person, but expect to budget a good weekend.

5. I had to install a bypass valve (standard on the S-trim) around the compressor for my car to idle correctly and eliminate the low speed hesitation probs I had. Not sure if this is common for the sc-trim, but that worked for me.

6. I had about 70k on the car when I installed the charger.

7. The noise is ok to me, I prefer the stealth approach but it wasn't available as an option on the sc-trim. My wife hates it, says its like running fingernails down a chalkboard, lol. The noise/whine is pretty much only during idle though. Can't really hear it any other time.

8. A quick change of the pullies and you will have over 10+ psi. Assuming your fuel system can handle it. A popular modification is to install a 7" crank pulley and powerpipe. Doing this will get you about 8-9 psi on a stock motor, and won't invalidate your warranty from vortech (which would happen if you change the compressor pulley). The compressor is supposed to be good for 20 psi and has the same potential as the S-trim. But you need to spin it relatively faster to get the same output as the S. I haven't checked my boost output yet, still in the process of installing the gauge. I still have the stock pullies on mine. But that's gonna change soon!

[Mitch Peoples]

Remember to use the on-line Vortech impeller speed calculator when changing pulleys. You may be able to push up to the max impeller speed, but as you approach max, you exceed the efficiency of the blower. You will be producing much hotter air, which will require you to adjust timing, fuel, etc and may actually reduce your performance without additional modifications.

GTFiveO is right about the bypass valve. Aside from aforementioned reasons, boost has nowhere to go when you abruptly step off the gas except back against the compressor. Better to have it bypass, even at the (relatively) lower boost levels of an A-trim.

Since Vortech factory FMU's use fixed adjustment technology, if you have the money to invest, I would highly recommend a Vortech Super FMU. While these are now considered archaic by todays standards of EPEC and PMS controls, the SFMU can do quite a bit. It functions as a standard fuel regulator, it lets you adjust fuel pressure rate of rise by lb of boost, it will also let you taper or set the top fuel pressure pressure increase based on a maximum boost level.

[vuvman2]

Thanks

[91GTFiveO]

I forgot to mention that the A-trim is no longer being manufactured (for the last several months) and has been replaced by the sc-trim which is a modified S-trim. This is definitely a plus for us budget guys. But I'm sure you can find an A-trim still on the shelf somewhere if you look hard enough and if that's what you really want.