ProCharged Can-Am - Raising the bar

[GTWayne]

This thread contains debate and conjecture, old fashioned maybe, but something that seems to have been lost over time and I for one welcome it. Arguing on a forum like this is pointless and futile.

[Omerta]

GTWayne said:

This thread contains debate and conjecture, old fashioned maybe, but something that seems to have been lost over time and I for one welcome it. Arguing on a forum like this is pointless and futile.

Good call. Seems to be a lot of good thinking and experience talking here - no idea who's "right", and TBH don't care - I just hope the differences continue to be debated without the all-too-common descent into toy-throwing

[eliot]

going back to the first page scuffers said:

38mm may sound big, but in terms of it's airflow, it's not, they are designed for turbo's where they only have to dump a limited volume of air, not a continus high volume.

if you really are making the power you think, you are looking at some 1,200+ CFM of air
have a think about how that's going to get though a 38mm valve etc...

At low load (cruise / idle) its not producing 1200 cfm, therefore it can easily flow out a 38mm DV.
At high load / rpm, the DV is closed and the engine is injesting all that goodly boost

Dave stated he has took readings before the throttle body and there is no boost, therefore the blower isn't being laboured - therefore the load on the engine is reduced (not eliminated though).

So I'm still not clear what the issue is.

[crafty]

eliot said:

So I'm still not clear what the issue is.

Its quite simple .....Scuffers has a pretend Ultima.... so he must be wrong.

Edited by crafty on Friday 1st August 11:18

[martinlaw]

I know very little about superchargers etc. but I do know Dave and the car.

I have 100% confidence in Dave's abilty and knowledge in these matters, the Can-am goes like **** off a shovel.

I am sure there are many alternative ways of putting these things together, does it really matter how it is, surely it is the end result that really matters.

Martin.

[qwick]

martinlaw said:

I know very little about superchargers etc. but I do know Dave and the car.

I have 100% confidence in Dave's abilty and knowledge in these matters, the Can-am goes like **** off a shovel.

I am sure there are many alternative ways of putting these things together, does it really matter how it is, surely it is the end result that really matters.

Martin.

A good point, and it's good that people have alternative views and suggestions. I hope we can keep discussions here as constructive as possible and lift ourselves about blatant insults as those achive anything positive.

Frankly I'm here for advice and to learn, I don't know who's right or even if there is a right but I'm open to reasoned argument, education and recommendation, that's what I'd like to see more of. I've been educated a fair bit in this thread but am disappointed by the level of condemnation of alternative ideas, an apparent intolerance of learners and an ability to leap down each other's throats rather quickly that I'm sure wouldn't happen if we were all sat around a table in a pub.

Let's puuuhleease try keep it friendly!

Edited by qwick on Friday 1st August 18:29

[Thevet]

qwick said:

A good point, and it's good that people have alternative views and suggestions. I hope we can keep discussions here as constructive as possible and lift ourselves about blatant insults as those achive anything positive.
I've been educated a fair bit in this thread but am disappointed by the level of condemnation of alternative ideas, an apparent intolerance of learners and an ability to leap down each other's throats rather quickly that I'm sure wouldn't happen if we were all sat around a table in a pub.

Let's puuuhleease try keep it friendly!

There's a lot of history in the two main sides of the debate, and although I hate arguments, I quite like this eternal intolerance, it makes me smile after a stty day, so don't everyone give up completely. And there is edumacashun in here as well.

[Scuffers]

crafty said:

eliot said:

So I'm still not clear what the issue is.

Its quite simple .....Scuffers has a pretend Ultima.... so he must be wrong.

and you wonder what comments like this make me think about you?

At the end of the day, as said, there are always different ways of doing things, what you have to consider is that they all have their good and bad points, blindly following the heard and ignoring the issues is all well and good, but you are never going to learn anything...

I am sure the car does wotj and go fast, but that's not the point i was trying (and cleary failing) to get accross, I bet it's cruse fuel consumption is shocking, but judging by Pete's AFR vid, that's looking par for the corse!

[deadscoob]

Scuffers said:

crafty said:

eliot said:

So I'm still not clear what the issue is.

Its quite simple .....Scuffers has a pretend Ultima.... so he must be wrong.

and you wonder what comments like this make me think about you?

At the end of the day, as said, there are always different ways of doing things, what you have to consider is that they all have their good and bad points,

I am sure the car does wotj and go fast, but that's not the point i was trying (and cleary failing) to get accross,

If you took a moment to actually think about what and how you're posting, perhaps people would took your comments on board and be more objective.

If you go on a forum and spout off that people are wrong, patronise them and insist they have made a bodge, that's probably not the way to do it.

You didn't reply to stevieturbos comments? Perhaps as you've fitted 100s of S/Cs, you can explain the benefits of both types and go over why aftermarket manufacturers favour Daves install method, which is (according to you) clearly a bodge?

[Scuffers]

deadscoob said:

If you took a moment to actually think about what and how you're posting, perhaps people would took your comments on board and be more objective.

If you go on a forum and spout off that people are wrong, patronise them and insist they have made a bodge, that's probably not the way to do it.

You didn't reply to stevieturbos comments? Perhaps as you've fitted 100s of S/Cs, you can explain the benefits of both types and go over why aftermarket manufacturers favour Daves install method, which is (according to you) clearly a bodge?

Nice....

If you CBA to read what I have already posted on the subject, you would already know what the issues are, but you cleary have not and don't understand, not that this stops you having a go I note...

Anyway, just so that don't have to read back, the issue is that the SC will be pushing as much air as it can at all times, irrelevant of where the throttle is.

Now, if it's going to provide any decent levels of boost in the mid-range on throttle, think about what it's moving at the same engine speed with the throttle closed and it now venting said air though a 38mm dump valve.... (you also might want to consider that although it's a 38mm valve, it's flow characteristics will be more akin to a 30-32mm un-impeded pipe).

Personally, I can't see how it can move this volume of air *without* building up some pressure, all be it maybe only a relatively small level.

Now, the drag the SC put's on the engine is partly made up of mechanical drag/gearing losses and then a component of drag related to flow/boost, either way, it's going to be higher in this setup than one where the throttle is ahead of the SC (and thus running in a partial vacuum).

as I keep saying (and you keep not listening/understanding) this is nothing new, people figured this stuff out many years ago, for example, Turbo Technics went down the very same learning curve when they first started playing with Rotrex SC's 10+ years ago, they ended up move the throttle before the SC to get round these issues.

Know doubt you will now retort with some more un-informed babble, maybe with yet another childish insult thrown in for good measure?

[CanAm Dave]

Scuffers said:

crafty said:

eliot said:

So I'm still not clear what the issue is.

Its quite simple .....Scuffers has a pretend Ultima.... so he must be wrong.

and you wonder what comments like this make me think about you?

At the end of the day, as said, there are always different ways of doing things, what you have to consider is that they all have their good and bad points, blindly following the heard and ignoring the issues is all well and good, but you are never going to learn anything...

I am sure the car does wotj and go fast, but that's not the point i was trying (and cleary failing) to get accross, I bet it's cruse fuel consumption is shocking, but judging by Pete's AFR vid, that's looking par for the corse!

Scuffers

I am not blindly following the heard as you put it but I'm using a standard and fully tested and documented way of installing a centrifugal supercharger. My valve does its job of dumping the air to atmosphere. As I have said already I have measured the pressure behind the throttle plates and there is none.

Most OEM setups use roots/screw style superchargers and due to there position on the engine have a built in bypass. By doing this there will be less parasitic power loss. But I was always talking about my setup. A ProCharger setup! Hence my thread title.

My cruise fuel consumption is not shocking in fact on a run a week or two back I got 20mpg. Considering that's a 6.3litre chevy running a supercharger I'd say that's good. If you read these things a little closer then you would know that Pete is running a carb and I am running efi. My AFR ratios are always going to be where they need to be! A carbs state of tune is always going to be a compromise! So par for the course it is not!

Regards Dave

[eliot]

Scuffers said:

Know doubt you will now retort with some more un-informed babble,
maybe with yet another childish insult thrown in for good measure?

Why dont YOU produce a diagram or photos of the 100's of superchargers you have fitted. Then add the maths illustrating your point; i.e at x rpm the engine requires y flow and the s/c is producing z flow. Then we can all be informed and learn alternate ways of looking at things.

[Scuffers]

CanAm Dave said:

I am not blindly following the heard as you put it but I'm using a standard and fully tested and documented way of installing a centrifugal supercharger.

to be fair, that comment was not aimed or intended at you....

[deadscoob]

Simon,

I'm not sure where the insult was there? Unless you take someone mentioning it is better to think about what you post, before you post as an insult?

Anyway.....

You mention you weren't aiming your comments at Dave, but what was this aimed at?

"Look, I am not going to ardue with you, you cleary have it in your head you are right, but suffice to say, you are not.

running a dump-valve on a SC like you are is a bodge, period.I am sure your now going to argue till the cows come home, etc etc, but that is never going to make you right, except in your own little world."


"At the end of the day, as said, there are always different ways of doing things, what you have to consider is that they all have their good and bad points, blindly following the heard and ignoring the issues is all well and good, but you are never going to learn anything...

I am sure the car does wotj and go fast, but that's not the point i was trying (and cleary failing) to get accross, I bet it's cruse fuel consumption is shocking, but judging by Pete's AFR vid, that's looking par for the corse!"

The point you were trying to make, as I read it, is that Daves setup is a bodge - as you said above. So, as I mentioned above, perhaps you'd like to explain the pros and cons of both setups, and if this is the wrong method, why do so many SC manufacturers produce to the same principle design?

[Scuffers]

deadscoob said:

The point you were trying to make, as I read it, is that Daves setup is a bodge - as you said above. So, as I mentioned above, perhaps you'd like to explain the pros and cons of both setups, and if this is the wrong method, why do so many SC manufacturers produce to the same principle design?

easy, they don't.

I cannot think of a single Mainstream OEM SC setup that uses a dump valve like this (even if you excude the Roots/Screw/Sliding Vien/Scroll/etc. types)

only reason I can see for doing this is it's cheaper for an after-market install as you don't have to make the hardware to move the throttle(s) etc.

Edited by Scuffers on Saturday 2nd August 11:34

[eliot]

Scuffers said:

I cannot think of a single Mainstream OEM SC setup that uses a dump valve like this (even if you excude the Roots/Screw/Sliding Vien/Scroll/etc. types)

This is getting tiring now. Can you show us a OEM centrifugal setup that plumbs it in the way you state or perhaps answer my question a few up.

[738 driver]

Errrrr.... so there are no noticable differences between a direct drive centrifugal compressor and a gas driven one???????????????

[Scuffers]

eliot said:

Scuffers said:

I cannot think of a single Mainstream OEM SC setup that uses a dump valve like this (even if you excude the Roots/Screw/Sliding Vien/Scroll/etc. types)

This is getting tiring now. Can you show us a OEM centrifugal setup that plumbs it in the way you state or perhaps answer my question a few up.

actually, I am struggling to think of a single OEM that uses centrifugal chargers!

if you look at Rotrex's own installation guidelines, their prefference is to put the throttle ahead of the SC...

tell you what, you find one that's not like this...

738 driver said:

Errrrr.... so there are no noticable differences between a direct drive centrifugal compressor and a gas driven one???????????????

Not sure what your getting at? compressor wise, there is little to differentiate a centrifugal SC compressor from one on a turbo..

the only real difference is one is 'locked' to engine speed, the other to load (effectively)

[eliot]

Scuffers said:

eliot said:

Scuffers said:

I cannot think of a single Mainstream OEM SC setup that uses a dump valve like this (even if you excude the Roots/Screw/Sliding Vien/Scroll/etc. types)

This is getting tiring now. Can you show us a OEM centrifugal setup that plumbs it in the way you state or perhaps answer my question a few up.

actually, I am struggling to think of a single OEM that uses centrifugal chargers!

if you look at Rotrex's own installation guidelines, their prefference is to put the throttle ahead of the SC...

tell you what, you find one that's not like this...

So you have pretty much just contradicted yourself. First you state that dave's setup is all wrong and a bodge, out of the 100's of charger setup you have done - you have never done it etc et-al.
So I now ask you to give an example of how it should be done and you admit that you cant think of one.

I think we have flogged this dead horse beyond the grave.

ETA:
Rotrex instructions say:
http://www.rotrex.com/pdfs/Rotrex_C-type_superchar...

rotrex instructions on page 9 said:

The most energy efficient solution is to have the throttle body positioned upstream of the supercharger. This will minimize the pump work by the supercharger, thus minimizing fuel consumption under part load because of the thin air situation around the impeller at throttle angles less than 90„a. Also a re-circulation valve can be
avoided in this type of set up.

A somewhat simpler approach (recommended for most aftermarket applications) is to leave the throttle body at the original position. If you choose to position the throttle body downstream, a re-circulation valve is recommended.If the valve is omitted the supercharger will create noise under deceleration caused by surge.
Surge occurs when the supercharger keeps making pressure at low airflow forcing the compressor to work outside the intended operation area. This will be most noticeable on high boost applications under high engine rpm with the throttle closed (deceleration). The re-circulation valve will prevent surge by allowing air
to circulate from the pressure side of the supercharger to the inlet side of the supercharger under manifold vacuum conditions

The recirc valve is specified because of the air mass meter which Dave doesn't have, therefore his atmospheric dv is fine.
I'm not reading any dire warning about how its a "bodge" to use your words. They say fit a recirc (or dump) you will be fine, which is how daves is configured.

Indeed from a safety point of view, with the TB before the S/C, if any of your plumbing develops a leak or pipes split - the engine will rev uncontrollably (assuming its MAP based, not MAF or TPS) - which could get interesting.

Edited by eliot on Saturday 2nd August 14:25

[stevieturbo]

So Scuffers.

Can you shows us your data logs from when you tested pressure at various points in the intake plumbing, from blower right through to engine ?

Can you tell us why Procharger, Vortech and Paxton all use typical discharge style BOV's on their centri setups ?

Can you show me anyone that uses a true bypass style on a centri ? As you are thinking....can you show me any single OE manufacturer that even uses a centri ??? No.

Although....you could class a re-circulating BOV as a bypass to a degree....just plumb the VTA BOV back into the mouth of the blower.
Which way would air then flow ??? Exactly the same as if it was a VTA.

Situating the TB in front of the blower is fine......if the plumbing is short, and there is no intercooler.
And then are the oil seals within the blower safe for handling vacuum ???

Throw the rather important intercooler on a boosted engine, and you add a huge volume of air. Now who in their right mind wants that huge volume between the TB, and their cylinder ??

Does the TT Rotrex system use an intercooler ? If so, how is throttle response affected from that large volume of air behind the throttle ??



I have done testing, monitoring pressure before the IC, after the IC, and of course in my intake manifold, all when I was running a pair of Greddy BOV's ( 38mm each )
Yes there was a pressure build up, but it isnt that big all things considered. I think my worst case would have seen about 6psi build up before the TB during normal driving.
Given blower size and speed, this wouldnt bother me at all. But this was with a pair of BOV/DV's intended for a turbo application, so they were not opening as soon as they could have been. At cruise, Im almost sure they were open only a very small amount...if at all. Certainly at idle they were closed.
With a more suitable Mondo in place, it is open at idle, and without doubt at cruise etc. So I havent felt any need to log pressures in the IC anymore, nor do I care TBH.
I was only logging in the first place, to test for IC restriction. The fact that some very light pressure might build up, is of little importance.

With the Mondo in place, Id say any pressure would be less than 1-2psi....and the Mondo is one of those bodge BOV's you mention, despite Vortech reccomending it.
Go figure.

If I was going to get that fussy, Id try and source a way of physically dropping the drive to the blower on demand, like the modern...and unreliable Mercedes blower cars do.

But why overcomplicate things ? Its a performance car we are talking about after all....not a super mega efficient install. If that was my main concern, I'd be tuning a diesel.
As things stand, I dont think mine is hard on fuel at all, all things considered.