JHM stage 1 supercharger kit

[lengster1]

I run no cat d/ps and full milltek system so very free flowing,inlet manifold has had Mrc treatment too,so with this in mind what gains do you think this charger would add roughly,I have a new stock clutch fitted,would this be up to the job? I never launch the car as I have too much mechanical sympathy.The lag effect through long induction piping is a concern,what are your thoughts on it?

[esp_mm-270]

Lag is a combination of pressurising the system from charger output to the cylinder inlet and the time it takes the charger to spin up. The Vortex itself is quick on spin up and will flow 800bhp

[m14rrv]

At last mate!!!! I can't wait to see it

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Lag is a combination of pressurising the system from charger output to the cylinder inlet and the time it takes the charger to spin up. The Vortex itself is quick on spin up and will flow 800bhp

Chargers don't have to spin up

[RossDagley]

Lag is a combination of pressurising the system from charger output to the cylinder inlet and the time it takes the charger to spin up. The Vortex itself is quick on spin up and will flow 800bhp

Chargers don't have to spin up

*super

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bah

[esp_mm-270]

Spin up, create internal pressure la la la......

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It's pretty easy to work out for a positive displacement charger as if you know how much air the charger is moving relative the intake volume and the amount of air the engine is consuming.
For the centrifugal its more tricky as the air is pre-compressed inside the charger.

[sakimano]

I run no cat d/ps and full milltek system so very free flowing,inlet manifold has had Mrc treatment too,so with this in mind what gains do you think this charger would add roughly,I have a new stock clutch fitted,would this be up to the job? I never launch the car as I have too much mechanical sympathy.The lag effect through long induction piping is a concern,what are your thoughts on it?

Stock downpipes are 2.61" and taper to meet the 2.36" catback exhaust which itself has a few crimps and restrictions. Full 2.5" Milltek would in my opinion/estimation/experience not add much vs. a car with stock downpipes with precats gutted, and stock exhaust. That's both on a naturally aspirated car, and similarly very little difference on a supercharged car.

To that end, you'd still benefit from most of the gains discussed earlier. The MRC tune probably gives you a bit of a bump and that's really the only other delta I think you'd miss out on vs. the gains going from stock to JHM stage 1.

There is no lag effect. As ADSGREEN mentioned above, a supercharger does not experience lag the way a turbo does. A turbo will literally add next to no air to the system until exhaust gases are sufficient to drive the turbo and in turn drive air from the clean side into the engine. It requires RPMs to meet a certain level before the exhaust is adequate, that is often 2000-3000 RPM for a smaller frame turbo (or a medium/large turbo fed by a large engine) or 4000-5000 RPM for a bigger turbo on a smaller displacement engine. With a supercharger, it is not driven by a wheel driven by exhaust gases...it is driven by a belt that is attached to the engine's own crank pulley. So as soon as the engine is spinning, the supercharger is being driven, and is working.

As I said, having driven a JHM stage 1 B7 S4, a JHM stage 1 B7 RS4 and a JHM stage 2 B7 RS4, there is no lag. It is just a steady addition of power and torque, and at high RPMs it is most evident. Some of the TVS series superchargers deliver more of a hit down low (bigger torque) but run out of steam at high RPMs.

There are 2 ways to look at it:

1. you can fill the 'void' that people feel the NA RS4 has which is torque downlow, and a TVS unit does very well in this regard as in the APR kit.
2. you can mate a supercharger that does well down low, and really excels at high RPMs...which is the RS4's forte. 8000 RPM. That would be a centrifugal supercharger, like the TTS Rotrex or the JHM Vortech.

Personally I like the latter. Not often am I sitting at 2500 RPM thinking 'I wish this car made more torque here, at an RPM I shouldn't really be driving at if I want to accelerate'. Reality is if you're just relaxing and cruising around at low RPMs, it's pretty rare that you want to hoon the car, and even if you do, you can downshift. On the other hand, when you buy an acceleration modification like a supercharger, you're likely to be enjoying that extra 100-200 hp at high RPMs and as you work through the gears. To that end, you will not see 2500 RPMs in that scenario, so why buy a supercharger that excels where you aren't pushing the car?

[lengster1]

Thanks for that,but I run no cat down pipes so was wondering how this would figure in in terms of overall improvement from were I'm at now versus were I could be with this kit fitted?

[lengster1]

I suppose, I'm saying that I've already improved the airflow and performance of my car would this negate some the power increase of this kit?

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I suppose, I'm saying that I've already improved the airflow and performance of my car would this negate some the power increase of this kit?

Doesn't always work that way (things don't stack like in GT5 )
What is good for n/a doesn't always mean is good for forced induction.
The changes to the intake manifold will do pretty much nothing with the supercharger. The no cat exhaust will help a lot and probably be very useful.
It all depends where the weakest part of the system is.

If the standard exhaust isn't the point of most restriction with a supercharger install then any changes will be marginal.

[bam_bam]

Ram air will give you a 30% uplift.

[lengster1]

That is pretty much how I was seeing it adsgreen,always accepted the system was purely for noise and worth every penny at that! I figured no cats must be of serious advantage in flow given there pretty restrictive,I would be very happy with anything close to 30% gains but if was a lot less given were I'm at already it might not be quite so attractive for me personally?it would be nice to see some Dyno plots to see torque delivery etc

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Sorry badly worded - I mean any changes to the exhaust will be marginal.