Superchargers ?

[tk421]

I'm not going to get into the BOV debate but as far as I know the level / presence of boost is determined by the gearing (pulleys) of the supercharger and whether or not the throttle position is passed 30% (in which case the magnuson flap is shut and boost builds). The supercharger does have a bypass valve on the top of it. I presume this was a pressure vent of some sort as well - maybe not dunno really.

The reason why a hotside doesn't like idling is that the path between the AFM and the throttle body mounted in the manifold is lenghthened a lot with this configuration as there is a reasonably lengthy pipe from the AFM to the supercharger on the right hand side then another reasonably lengthy pipe from the super to the inlet manifold.

My basic understanding is that the factory AFM working with the factory computer and the piggyback has a hard time doing the proper calcs when revs suddenly drop and it has to adjust the fuel mixture back to normal to keep it idling - even if the engines base idle is adjusted up.

In stage one tunings case it doesn't help that their fueling solution the \"elf\" (at least at this point) really just doesn't work. Stage one have been promising for more than 6 months to come up with a map that consistently works but to date AFAIK they have not delivered (couple this with generally poor customer service and I was pretty sure I wouldn't give then my money!)

In a mechanical sense my understanding is the problem is to a reasonable degree due to the increased throttle volume as a result of the pipe ie air between the AFM and the throttle body (particularly with intercooling) , If anyone wants to put this more eloquently fee free.

I know you will point to the \"see, they should be using a full ecu\". I don't disagree and I'm sure it would improve the behaviours. The fact is Stage one have been marketing their packaged solution like it works superbly and as such people have been buying it. The reality is at least at this point for the lions share of their customers it doesn't. The hotside config is a contributor to the prob.

For those that don't want to spend the extra coin on a full ecu , don't have an over the top HP target (approx 146kw I'm pretty sure was close to the top SP number at our last dyno day- based on this the lets say 142-150kw of the FFS is in pretty good company), want a package that behaves largely like the standard vehicle when you want it to (ie at a set of lights and warming it up in the morning) and a sustained push in the back with some cool engine noises when you want it to (ie every other time ) - the FFS kit seems to fit the bill. Read some comments on miata net from people that have the kit or have dealt with tom. They seem quite happy.

Whilst I have learned a lot from my family over the years re car tinkering ( My dads been a mechanic since he was 16, built cosworth engines for jim richards in his day, raced speedcars at parramatta etc he built himself which I used to help with) I don't claim to be any sort of authority on this stuff, its just what I have read like any of you would do and it made sense to me. As far as i'm concerned If a lot of people have said that they fitted the kit and it works like the guy that flogs it said it would then thats good enough for me - and this seems to be the case

Cheers

Steve

[The Pupat]

How is this a by-product of the hotside placement of the supercharger? Sounds like the kit doesn't have a BOV (note to ricers this is what a BOV is used for... to correct fuel maps when using a AFM).

Can you explain this in a bit more detail please, I don't follow. A VTA BOV will root your fuel maps if you have an AFM (the ecu is fuelling for air which is not going into the chamber). Do you mean a recirc BOV?

recirulating one. As the throttle shuts, or more accurately a vacuum is built up in the intake manifold the Bypass Valve (or recirc BOV whatever you want to call it) opens up and allows any pressure built by the supercharger to vent out into the intake before the AFM, the supercharger then sucks this air back in and keeps recirculating it whilst the motor sucks off a tiny little amount the entire time to keep itself running as such in this system the AFM only then has to supply (measure) the amount of air the motor is using, as such the EFI system then only reads how much air the engine is using and all is happy in the AFR world. Incidently the Bypass Valve can also improve fuel ecconomy for this exact reason, since the air isn't pressurised whilst the valve is open the drain on the motor is only the amount of energy required to turn the supercharger and not the amount required to turn the supercharger and, far more significantly, pressurising the intake the entire time. Hope that makes some sense.

[The Pupat]

The reason why a hotside doesn't like idling is that the path between the AFM and the throttle body mounted in the manifold is lenghthened a lot with this configuration as there is a reasonably lengthy pipe from the AFM to the supercharger on the right hand side then another reasonably lengthy pipe from the super to the inlet manifold.

My basic understanding is that the factory AFM working with the factory computer and the piggyback has a hard time doing the proper calcs when revs suddenly drop and it has to adjust the fuel mixture back to normal to keep it idling - even if the engines base idle is adjusted up.

That makes no sense to me. If the intake path was making the difference then why isn't there a problem with the factory computer, The have the worlds longest intake path from the factory and I find it hard to believe the supercharger kits make it much longer at all, maybe 30cm-1 Foot longer at most, which given the factory one would be 6 foot at least would make bugger all difference. I think you'll find something else is to blame and not the hotside setup.

[The Pupat]

Sounds like the kit doesn't have a BOV (note to ricers this is what a BOV is used for... to correct fuel maps when using a AFM).

I have always been under the impression that the function of a BOV is to reduce the pressure in a blow-through forced induction system when the throttle body is closed. This avoids pressure spikes and stops a pressure wave from moving backwards and forwards from the throttle plate to the compressor blades which slows down the compressor blades and can potentially damage the turbo (a supercharger isn't as prone to damage as it is belt dríven).

That's the wives tale but that's a completely different arguement. Basically the definitition in the other post I gave is the same sorta thing that is occuring.

[Boags]

Thakns for that... That is what I thought.

I think you'll find something else is to blame and not the hotside setup.

I have to agree, it should make close to zero difference with a slightly longer intake tract. If it was a VTA type BOV, it might be running really rich when you get off the gas, flooding the engine and stalling. The air comes through the AFM (or MAF) and then is expelled, not burned. The ecu adds fuel for it though; hence, flooding.

Just a thought.

Boags

[KIJIMA]

As much as I am enjoying the banter too and fro, and managing to keep up with understanding most of it , I wont be parting with any money until I get to drive a car with the FFS setup on it, then Im better equipped to make a decision. If I wasnt impressed with the drive, I wouldnt go ahead with it.

That being said, so far here is what I like about it. SP power or greater for around 5K, its removable if the need arises (if and when I sell my car etc...) plus I love the whine of a supercharger.

[tk421]

That makes no sense to me. If the intake path was making the difference then why isn't there a problem with the factory computer, The have the worlds longest intake path from the factory and I find it hard to believe the supercharger kits make it much longer at all, maybe 30cm-1 Foot longer at most, which given the factory one would be 6 foot at least would make bugger all difference. I think you'll find something else is to blame and not the hotside setup.

Seems to make sense to Daniel from Mania, as he made this point to me as well (not that I consider him the authority on everything but hey).

Re the throttled volume if this was no problem whatsoever then how come a couple of different manufacturers make custom inlet manifolds to be used with a Hotside super so that throttled voume is less? (can't find a link off hand but they are out there)

Have a look at this photo and tell me if you still think its 30cm (consider the supercharger and its volume is obviously in the intake path..)

https://2693453429.monstercommercesites ... &ProdID=55

Think I just let you all shout me down for the last time now and I'll go fit my kit and enjoy...

[JBT]

Hurry up and put it on so you can tell us how the fitting went and, most importantly, how good it goes I'm keen to hear.

[Okibi]

I've been searching http://www.fastforwardsuperchargers.com for photos of the system installed on a car.

That 3d thing doesn't work for me and the instructions don't seem to show a \"finished\" product shot.

Can anyone point me in the right direction?

[tk421]

http://www.fastforwardsuperchargers.com ... d.php?t=31

Here's mockup picktures of what a RHD would look like (with the exception of the master and slave cylinder!) from the FFS forum. The rotation of the bypass valve on the SC is said to be the only change required - chris will be able to confirm this for us shortly though

[The Pupat]

Seems to make sense to Daniel from Mania, as he made this point to me as well (not that I consider him the authority on everything but hey).

Re the throttled volume if this was no problem whatsoever then how come a couple of different manufacturers make custom inlet manifolds to be used with a Hotside super so that throttled voume is less? (can't find a link off hand but they are out there)

Have a look at this photo and tell me if you still think its 30cm (consider the supercharger and its volume is obviously in the intake path..)

https://2693453429.monstercommercesites ... &ProdID=55

Think I just let you all shout me down for the last time now and I'll go fit my kit and enjoy...

Well that's not just a hotside setup by the looks of it either. Instead of leaving the throttle in the standard position attached to the standard intake manifold, it looks to me like they've moved it infront of the supercharger. I shake my head really and wonder what they were thinking. If they left the throttle attached to the standard intake manifold and ran it "blow through" instead of "suck through" like they all seem to want to do I reckon they would have far less problems. I'm starting to wonder if these people played with too many carbied supercharged V8 when they were younger.

[Craig]

That Titanium SE is looking better every day eh Dan!

[The Pupat]

1/ You cannot feed a positive displacement supercharger into a down stream throttle without somehow arranging for an escape path for the air when the throttle slams shut at high engine rpm, as when gear changing.

Doing this successfully is not as easy as it initially looks. Doing it very cheaply for a kit is even more difficult.

Plumpback Recirc BOV / Bypass Valve would do the job like you said would it not? Obviously running a wastegate would be a lot better but then as you said more cost involved. Actually I met a bloke that built a twincharge RB25 using a external wastegate to bypass the supercharger said the part throttle response etc was a lot better as you can feed the boost into the motor at part throttle rather than running full boost the whole time.

Closer to the best of both worlds I'd think especially since you remove of the need to water/meth cool or even worse in my mind run it rediculously rich to cool the intake down like the e-cool seems to do. Ohh well each to their own I guess.

[rhysk]

Josh, that is why I am so slow

It has been done on the M45 kits, here is some light bedtime reading on the subject:
http://forum.miata.net/vb/showthread.php?t=203287

Essentially, it is not like a turbo in that the compressor doesn't slow down when you lift the throttle. You have to flow a lot of air in not a lot of time to keep your belt and piping intact.

Tooling around town, mine takes about 1/4 of a second to respond - not immediate, but not much worse than stock. With some revs, it is almost instantaneous - better than a naturally aspirated with plenum chamber.

[The Pupat]

Josh, that is why I am so slow

I thought that was just cause it had one of those crappy supercharger things on it (that is way too small ).

So when are we going to put a hairdryer on it to "give the supercharger a hand"?

Come one at the very least upgrade the supercharger to a 12/71!