Supporting mods for HVT 1900 harrop supercharger

[Torborg]

Hi all.

I have a vt auto ls1 senator, and am wanting to add a harrop HVT1900 supercharger. I've never been down this road before, so just have a few questions. I'm hoping to get a balance between street performance, drivabilty, and fuel economy. I'm also motivated to avoid police attention/legality issues as much as is reasonably possible.

My car currently has 3.9 diff gears. Is it worth keeping them or changing (as has been suggested by a tuning shop)?

Other modifications are full exhaust and cam (I'm planning to change the cam back to standard), and mafless tune (which I'm planning to change to vz standard intake with maf tune).

Can anyone suggest other supporting mods that might interest me?

[HEKYEH]

What's your budget?

If you are going to change the cam, why not put in a cam that will compliment the blower?

What sort of exhaust is it? Size? Just cat back? Or also headers? If so, what sort? Size?

What about brakes? Might need some more stopping power...

All depends on how much coin you want to throw at a car of that value...

[white lie]

In the process of doing the same really, i've gone with the MP1900 though.
My car was really set up for NA work. 4500 stall, 3.91's, 228/232 cam etc.

For the time being, i'll be running it as is. It will be brutal (or maybe fun?) on the street but should be very well setup for the strip. If it runs out of puff in 3rd gear down the 1/4 then i'll look at dropping the gears back to 3.73's or 3.45's. Plenty of people are willing to swap for 3.9's, so i'd run with it and see what you think before making your mind up.

My cam isn't really boost orientated but again i'll see how it goes. It will obviously work, but if it blows a heap of boost out the exhaust, then i'll look at changing it but not before hand. Unless your cam is something like a TK, i'd suck it and see. There's guys running 232/234's etc with these blowers still making good power so it's not all bad.

Costs can and will quickly add up though.
I got my kit on special at 7K and would have spent double that again on other bits and pieces by the time its on. If you don't over complicate things, you could get away with it around 10K if you do some work yourself.

[Torborg]

What's your budget?

If you are going to change the cam, why not put in a cam that will compliment the blower?

What sort of exhaust is it? Size? Just cat back? Or also headers? If so, what sort? Size?

What about brakes? Might need some more stopping power...

All depends on how much coin you want to throw at a car of that value...
Thanks for the reply.

The reason I wanted to go back to standard cam was to avoid issues with the police. From what I can tell, the blower is reasonably quiet, and doesn't look much out of place in the engine bay. Even if I get defected, it would be easy to remove.

If there is a cam that isn't overtly loud or lumpy, I'd consider it. Do you have anything in mind?

Exhaust consists of 4 into 1 pacemaker extractors (not sure of size), cats, and twin 2.5in cat back. I also have a set of vy2 hsv headers in the garage which i could change if they would make the car quieter.

The car already has the upgraded brakes (I think it was an option?) and I'm happy with them. I'd rather spend the extra money elsewhere. The transmission has already been strengthened, so I don't think there will be many issues there. If the transmission does get wrecked somewhere down the track, I think I'd consider a manual conversion.

Budget would be about $5K on top of the blower/tune.

[Torborg]

In the process of doing the same really, i've gone with the MP1900 though.
My car was really set up for NA work. 4500 stall, 3.91's, 228/232 cam etc.

For the time being, i'll be running it as is. It will be brutal (or maybe fun?) on the street but should be very well setup for the strip. If it runs out of puff in 3rd gear down the 1/4 then i'll look at dropping the gears back to 3.73's or 3.45's. Plenty of people are willing to swap for 3.9's, so i'd run with it and see what you think before making your mind up.

My cam isn't really boost orientated but again i'll see how it goes. It will obviously work, but if it blows a heap of boost out the exhaust, then i'll look at changing it but not before hand. Unless your cam is something like a TK, i'd suck it and see. There's guys running 232/234's etc with these blowers still making good power so it's not all bad.

Costs can and will quickly add up though.
I got my kit on special at 7K and would have spent double that again on other bits and pieces by the time its on. If you don't over complicate things, you could get away with it around 10K if you do some work yourself.
At the moment I'm running with a 237 242 cam and a 4000 stallie. It's fun to drive irregularly, but not really practical as a daily (which I'm looking to turn this into). The cam change isn't really an option, more a necessity.

I think your advice about the 3.9 diff gears is good. I'm sure it wouldn't be that hard to change down the track. Do you have any idea how different the car would be to drive with a diff change, as well as the difference in fuel use?

Cheers, Justin

[white lie]

Think of the swap in gear ratios's in NA form, will be similar but more pronounced with boost. If that makes sense? Due to the flat boost curves of these blowers, it won't have too much of an effect at certain/individual revs.

Now that you've mentioned the rest of the combo, i'd be looking to change cams. I too would go aftermarket rather than going back to stock. Something small but designed for boost should be relatively quiet if tuned right.