Let's talk about forced induction options
Discussion
Ok, my weekend trip to the 'ring highlighted that whilst my '96 Mk1 1.8 is good at turning and stopping, a tad more power would be beneficial.
So, where do I turn? Here's my thinking so far..
I'd like about 180bhp or so
I think s/c is my preference vs turbos as I like a linear power delivery
I want to take the car into somebody good, have the work done, pay them some money and then drive home
There seem to be so many systems and options - I just want a one-stop-shop solution
'Fettling' the system to get it running well is not really what I want - I want it to work from Day 1 and be reliable.
As you can see, I need some guidance.
Your thoughts?
So, where do I turn? Here's my thinking so far..
I'd like about 180bhp or so
I think s/c is my preference vs turbos as I like a linear power delivery
I want to take the car into somebody good, have the work done, pay them some money and then drive home
There seem to be so many systems and options - I just want a one-stop-shop solution
'Fettling' the system to get it running well is not really what I want - I want it to work from Day 1 and be reliable.
As you can see, I need some guidance.
Your thoughts?
Mark @ OnlyMX5ives on this forum is the obvious choice - £1.5k for a supplied and fitted second hand supercharger install that will likely do everything you ask... as far as I know he doesn't have any kits available at the moment, but if you speak to him I'm sure he'd let you know when he does.
IIRC Mr Fast on mx5nutz will also supply and fit superchargers (usually mini ones), so you could get an idea of price from him too.
I'm sure there are others who can offer turbos at a similar price, maybe they, or they who know about them can chime in here...
That said, IME, you'll need around 200 bhp + before you end up with anything all THAT potent in a straight line
IIRC Mr Fast on mx5nutz will also supply and fit superchargers (usually mini ones), so you could get an idea of price from him too.
I'm sure there are others who can offer turbos at a similar price, maybe they, or they who know about them can chime in here...
That said, IME, you'll need around 200 bhp + before you end up with anything all THAT potent in a straight line
piefacemate said:
Performance 5 in Uxbridge are another option for Superchargers.
Do bear in mind, however, that superchargers on MX5's are limited in ultimate power. If you want to increase the 180BHP in the future you'll have less scope and greater costs than with a turbo install.
Not sure that's strictly true, is it? What about the Kraftwerks/949Racing Rotrex supercharger - I believe that's capable of well into the 200 bhp realm if you take the restrictor plate off and is possibly a better option for the track than the usual MP45 or even M62 options?Do bear in mind, however, that superchargers on MX5's are limited in ultimate power. If you want to increase the 180BHP in the future you'll have less scope and greater costs than with a turbo install.
Yes you will need to upgrade the fueling, fit an intercooler and be able to map it, but that's the same with turbos at that power level, as I understand it.
youngsyr said:
piefacemate said:
Performance 5 in Uxbridge are another option for Superchargers.
Do bear in mind, however, that superchargers on MX5's are limited in ultimate power. If you want to increase the 180BHP in the future you'll have less scope and greater costs than with a turbo install.
Not sure that's strictly true, is it? What about the Kraftwerks/949Racing Rotrex supercharger - I believe that's capable of well into the 200 bhp realm if you take the restrictor plate off and is possibly a better option for the track than the usual MP45 or even M62 options?Do bear in mind, however, that superchargers on MX5's are limited in ultimate power. If you want to increase the 180BHP in the future you'll have less scope and greater costs than with a turbo install.
Yes you will need to upgrade the fueling, fit an intercooler and be able to map it, but that's the same with turbos at that power level, as I understand it.
My understanding was that the MP45/62 installs hit a ceiling of around 250BHP due to the relatively small size of the engine in the MX5 and the resultant drain caused by the supercharger. I'm sure it is possible to extract more, but the cost of doing so was disproportionatily high compared with turbo installs. The supercharger is running out of puff around 15psi, but even a GT2560RS turbo is good for 30psi or so.
To achieve greater than 150bhp, i.e. upping the boost beyond 5psi, you're starting to need intercooling, managed ECU's, 550cc injections etc. on turbo and supercharger installs, as you quite rightly say. However, with a turbo charged installed, once you've got these items you're simply remapping to achieve higher power figures, instead of having to change pulleys and plates and so on. Your limit then becomes, on both options, the ability of the car to cool itself, and the strength of the engine and drivetrain componants; I'm saying it's cheaper to go 200+bhp on a turbo, not that it's the only way.
Nor am I questioning the potential of supercharged installs - no doubt someone will be along shortly with their 500BHP monster install and prove me totally wrong - but offering my view on the benefits of both options. If I wanted 200BHP, and never, ever anything more, then I would select a supercharger as it's linear power delivery suits the car better. If I wanted 200BHP with the capacity to increase later, I would choose the turbocharger as it will be cheaper in the long-term.
I, however, reserve the right to caveat all the above as I may well be talking b
ks 
Well I don't know a huge amount about it, but put it this way, there is an MX-5 in the States running over 300 bhp on a rotrex supercharger.
The rotrex is not like the MP45 and M62 chargers, it's a different type and AIUI is essentially a modified turbo that is belt driven from the crank rather than having a turbine wheel like a turbo would.
It also has a trick oil system that increases low rpm boost.
I understand that the rotrex superchargers increase boost as a multiple (or possibly even square) of rpm, so boost increases massively the higher the rpm you go.
Kraftwerks have got around the issue of having no boost at low rpm and massive boost at high rpm by fitting a big rotrex supercharger that would provide ridiculous boost (I've read figures of 30 psi+) at the redline were it not restricted.
This means that it produces a reasonable amount of boost low down as it's big, without blowing your engine apart at the redline.
It also means that it's capable of huge power with virtually no additional spend on the charger - you just remove the restrictor plate.
Finally, these chargers are also better on track, as they don't produce their maximum boost until high rpm.
The rotrex is not like the MP45 and M62 chargers, it's a different type and AIUI is essentially a modified turbo that is belt driven from the crank rather than having a turbine wheel like a turbo would.
It also has a trick oil system that increases low rpm boost.
I understand that the rotrex superchargers increase boost as a multiple (or possibly even square) of rpm, so boost increases massively the higher the rpm you go.
Kraftwerks have got around the issue of having no boost at low rpm and massive boost at high rpm by fitting a big rotrex supercharger that would provide ridiculous boost (I've read figures of 30 psi+) at the redline were it not restricted.
This means that it produces a reasonable amount of boost low down as it's big, without blowing your engine apart at the redline.
It also means that it's capable of huge power with virtually no additional spend on the charger - you just remove the restrictor plate.
Finally, these chargers are also better on track, as they don't produce their maximum boost until high rpm.
youngsyr said:
Well I don't know a huge amount about it, but put it this way, there is an MX-5 in the States running over 300 bhp on a rotrex supercharger.
The rotrex is not like the MP45 and M62 chargers, it's a different type and AIUI is essentially a modified turbo that is belt driven from the crank rather than having a turbine wheel like a turbo would.
It also has a trick oil system that increases low rpm boost.
I understand that the rotrex superchargers increase boost as a multiple (or possibly even square) of rpm, so boost increases massively the higher the rpm you go.
Kraftwerks have got around the issue of having no boost at low rpm and massive boost at high rpm by fitting a big rotrex supercharger that would provide ridiculous boost (I've read figures of 30 psi+) at the redline were it not restricted.
This means that it produces a reasonable amount of boost low down as it's big, without blowing your engine apart at the redline.
It also means that it's capable of huge power with virtually no additional spend on the charger - you just remove the restrictor plate.
Finally, these chargers are also better on track, as they don't produce their maximum boost until high rpm.
Sounds interesting! I'll try to find the website and have a look, always eager to learn more.The rotrex is not like the MP45 and M62 chargers, it's a different type and AIUI is essentially a modified turbo that is belt driven from the crank rather than having a turbine wheel like a turbo would.
It also has a trick oil system that increases low rpm boost.
I understand that the rotrex superchargers increase boost as a multiple (or possibly even square) of rpm, so boost increases massively the higher the rpm you go.
Kraftwerks have got around the issue of having no boost at low rpm and massive boost at high rpm by fitting a big rotrex supercharger that would provide ridiculous boost (I've read figures of 30 psi+) at the redline were it not restricted.
This means that it produces a reasonable amount of boost low down as it's big, without blowing your engine apart at the redline.
It also means that it's capable of huge power with virtually no additional spend on the charger - you just remove the restrictor plate.
Finally, these chargers are also better on track, as they don't produce their maximum boost until high rpm.
One observation, however: If the rotrex unit is increasing boost exponentially as the engine spins faster arne't you going to end up with power delivery similar to a turbocharger? I suppose you've got some additional advantages; no turbo lag, more low down torque; but it sounds to me like the net result is a turbocharger with decreased efficiency. I do acknowledge that it's probably a better overall proposition in a race environment, however.
On the issue of low-down torque, an interesting fact for you: My turbocharging starts to spool at 3000rpm. At 3000rpm the car is producing the same power - 130bhp - as the NA engine at it's peak; turbos aren't as poor as producing low down power as they're made out to be, the feeling is just emphasised due to the rapid delivery once it fully spools and dumps it all in one go.
piefacemate said:
Sounds interesting! I'll try to find the website and have a look, always eager to learn more.
One observation, however: If the rotrex unit is increasing boost exponentially as the engine spins faster arne't you going to end up with power delivery similar to a turbocharger? I suppose you've got some additional advantages; no turbo lag, more low down torque; but it sounds to me like the net result is a turbocharger with decreased efficiency. I do acknowledge that it's probably a better overall proposition in a race environment, however.
On the issue of low-down torque, an interesting fact for you: My turbocharging starts to spool at 3000rpm. At 3000rpm the car is producing the same power - 130bhp - as the NA engine at it's peak; turbos aren't as poor as producing low down power as they're made out to be, the feeling is just emphasised due to the rapid delivery once it fully spools and dumps it all in one go.
I believe the Rotrex is touted as having the best elements of both a turbo charger and a supercharger, it produces instant throttle response and reasonable torque at low rpm, but can spin at ridiculous speed and produce a lot of boost at high rpm. Another nice feature is that it's virtually silent.One observation, however: If the rotrex unit is increasing boost exponentially as the engine spins faster arne't you going to end up with power delivery similar to a turbocharger? I suppose you've got some additional advantages; no turbo lag, more low down torque; but it sounds to me like the net result is a turbocharger with decreased efficiency. I do acknowledge that it's probably a better overall proposition in a race environment, however.
On the issue of low-down torque, an interesting fact for you: My turbocharging starts to spool at 3000rpm. At 3000rpm the car is producing the same power - 130bhp - as the NA engine at it's peak; turbos aren't as poor as producing low down power as they're made out to be, the feeling is just emphasised due to the rapid delivery once it fully spools and dumps it all in one go.
As for turbocharge cars not having low down torque, it is all relative as you say, but the point is that with a supercharger you have instant throttle response at any rpm and even with the rotrex you still get considerably more torque low down the rev range than on an NA and where a turbo would be off boost. The rotrex will obviously provide some boost at all rpms.
For example, I imagine your engine/turbo producing 130 bhp at 3,000 rpm would be producing considerably more at 3,000 rpm with a rotrex fitted, if the power at 7,000 rpm were similar. You might then find that the turbo produces more torque between 4,000 rpm and 6,000 rpm when it's fully spooled with the rotrex then catching up to match peak power at the redline (assuming your turbo is designed to produce peak power there).
The website with a discussion is here:
http://949racing.com/rotrexmiatasupercharger.aspx
Note that the Rotrex supercharger available in the full kit is the C30-74 which is available on its owned and advertised as being able to flow enough air for up to 310 US WHP.
Edited by youngsyr on Friday 28th May 17:33
totally off topic but i was reading in a magazine recently about an old racing car, like 40's F1 car or something that was spinning its supercharger up to 42psi.
the difference between exhaust and belt driven turbine is that generally it's easier to increase the speed of the exhaust driven turbine. however there's nothing to say that an s/c can't boost higher pressures than a t/c (tho you do get the arguement about the losses) or that the low range torque of a t/c is crap. its more to do with how they are set up a lot of the time.
the difference between exhaust and belt driven turbine is that generally it's easier to increase the speed of the exhaust driven turbine. however there's nothing to say that an s/c can't boost higher pressures than a t/c (tho you do get the arguement about the losses) or that the low range torque of a t/c is crap. its more to do with how they are set up a lot of the time.
Guys, thanks for you thoughts so far.
I just found these threads, having a read now, very useful:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.co.uk/gAssing/topic.asp?h=0...
I just found these threads, having a read now, very useful:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.co.uk/gAssing/topic.asp?h=0...
Edited by Matt UK on Friday 28th May 20:56
youngsyr said:
I believe the Rotrex is touted as having the WORST elements of both a turbo charger and a supercharger.
It doesn't have the efficiency nor power of the best turbo kits nor does it have the low down torque of the best SC kits.
What it is, is easy to package / fit
Edited for accuracy.It doesn't have the efficiency nor power of the best turbo kits nor does it have the low down torque of the best SC kits.
What it is, is easy to package / fit
piefacemate said:
I'm interested in seeing more info about the Kraftwerks installs you mention, I was under the impression that their kit was fixed at 5PSI like the Greddy turbo setups.
My understanding was that the MP45/62 installs hit a ceiling of around 250BHP due to the relatively small size of the engine in the MX5 and the resultant drain caused by the supercharger. I'm sure it is possible to extract more, but the cost of doing so was disproportionatily high compared with turbo installs. The supercharger is running out of puff around 15psi, but even a GT2560RS turbo is good for 30psi or so.
Why would you want/need 30psi anyway? Mine started out as a Greddy kit, is running a TD04h with proper management, supporting mods etc and (according to previous owner) dynoed 225 rwhp@13psi and 255rwhp@15psi. My understanding was that the MP45/62 installs hit a ceiling of around 250BHP due to the relatively small size of the engine in the MX5 and the resultant drain caused by the supercharger. I'm sure it is possible to extract more, but the cost of doing so was disproportionatily high compared with turbo installs. The supercharger is running out of puff around 15psi, but even a GT2560RS turbo is good for 30psi or so.
GravelBen said:
piefacemate said:
I'm interested in seeing more info about the Kraftwerks installs you mention, I was under the impression that their kit was fixed at 5PSI like the Greddy turbo setups.
My understanding was that the MP45/62 installs hit a ceiling of around 250BHP due to the relatively small size of the engine in the MX5 and the resultant drain caused by the supercharger. I'm sure it is possible to extract more, but the cost of doing so was disproportionatily high compared with turbo installs. The supercharger is running out of puff around 15psi, but even a GT2560RS turbo is good for 30psi or so.
Why would you want/need 30psi anyway? Mine started out as a Greddy kit, is running a TD04h with proper management, supporting mods etc and (according to previous owner) dynoed 225 rwhp@13psi and 255rwhp@15psi. My understanding was that the MP45/62 installs hit a ceiling of around 250BHP due to the relatively small size of the engine in the MX5 and the resultant drain caused by the supercharger. I'm sure it is possible to extract more, but the cost of doing so was disproportionatily high compared with turbo installs. The supercharger is running out of puff around 15psi, but even a GT2560RS turbo is good for 30psi or so.
But I agree that for the road / 99.9% of drivers would be more than happy at 250bhp 250lbs ft or less. I have 2 cars in around this power level and they are very fast and its easy to lose traction.
Also this power level is on the limit of breaking the box and the rods / pistons aren't far behind.
I've just had an Adaptronic & 550cc injectors fitted in my car and had it rolling road tuned at RE:Worx in Portsmouth. It still needs a bit of tweaking to the idle and very low load low throttle but otherwise I'm very pleased with it.
It now has a very linear power "curve". About 90bhp @ 2500, 145bhp @ 4000, 210bhp at 5500, 240bhp @ 6500. Not bad for 0.6 bar (about 9psi) and goes to show that you can't compare turbo & sc using boost pressure as a comparison, air flow is much more important and is what bigger superchargers are good at. Unfortunately I don't have a graph that shows torque but it feels very healthy
It now has a very linear power "curve". About 90bhp @ 2500, 145bhp @ 4000, 210bhp at 5500, 240bhp @ 6500. Not bad for 0.6 bar (about 9psi) and goes to show that you can't compare turbo & sc using boost pressure as a comparison, air flow is much more important and is what bigger superchargers are good at. Unfortunately I don't have a graph that shows torque but it feels very healthy
MX-5 Lazza said:
I've just had an Adaptronic & 550cc injectors fitted in my car and had it rolling road tuned at RE:Worx in Portsmouth. It still needs a bit of tweaking to the idle and very low load low throttle but otherwise I'm very pleased with it.
It now has a very linear power "curve". About 90bhp @ 2500, 145bhp @ 4000, 210bhp at 5500, 240bhp @ 6500. Not bad for 0.6 bar (about 9psi) and goes to show that you can't compare turbo & sc using boost pressure as a comparison, air flow is much more important and is what bigger superchargers are good at. Unfortunately I don't have a graph that shows torque but it feels very healthy
Good going, there are now quite a few mk2 MP62 cars knocking about now with the region of 250bhp.It now has a very linear power "curve". About 90bhp @ 2500, 145bhp @ 4000, 210bhp at 5500, 240bhp @ 6500. Not bad for 0.6 bar (about 9psi) and goes to show that you can't compare turbo & sc using boost pressure as a comparison, air flow is much more important and is what bigger superchargers are good at. Unfortunately I don't have a graph that shows torque but it feels very healthy
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