Engine Question.
Discussion
Does anyone know if a 450SE engine will accept a supercharger without a re build to alter the CR?
Basically is there any evidence anywhere that says the 450 engines had an unusually high CR. They certainly had more attention than the 400 engines as they have the larger sleeved 80mm plenums. Just wondering about the CR.
Cheers.
Basically is there any evidence anywhere that says the 450 engines had an unusually high CR. They certainly had more attention than the 400 engines as they have the larger sleeved 80mm plenums. Just wondering about the CR.
Cheers.
I missed the ebay charger tonight.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&am...
I was on my HTC Phone & it froze.
So, the Eaton jobbie will flow enough for a 4.5 Adam?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&am...
I was on my HTC Phone & it froze.
So, the Eaton jobbie will flow enough for a 4.5 Adam?
The Eaton M90 will flow enough for a 5.7L (and upto 14psi), not sure about an M83, having never come across one.
What Adam said about using composite gaskets to drop the CR is correct, used them myself and managed to get a 0.7 drop (9.75 to 9.05)
Most experts reckon that the standard pistons will handle up to 7psi of boost before the ring lands start to fail, I run mine at 4psi and have for the last 2 years with no adverse problems.
Would recommend looking at some form of intercooling if you intend to run with standard pistons
Chedder
What Adam said about using composite gaskets to drop the CR is correct, used them myself and managed to get a 0.7 drop (9.75 to 9.05)
Most experts reckon that the standard pistons will handle up to 7psi of boost before the ring lands start to fail, I run mine at 4psi and have for the last 2 years with no adverse problems.
Would recommend looking at some form of intercooling if you intend to run with standard pistons
Chedder
I have a graph for the M83 that shows it good for up to 5l, I'll dig it out soon. Wow that Sprintex went for over £800! I bought a spare one for 400 (not for sale though Wyn ;^) a year or so ago as an insurance policy.
I think the S102 would struggle a bit with a 450, the boost would be down to 5psi dropping to 3.
I think the S102 would struggle a bit with a 450, the boost would be down to 5psi dropping to 3.
pwd95 said:
Does anyone know if a 450SE engine will accept a supercharger without a re build to alter the CR?
Basically is there any evidence anywhere that says the 450 engines had an unusually high CR. They certainly had more attention than the 400 engines as they have the larger sleeved 80mm plenums. Just wondering about the CR.
Cheers.
Cripes !Basically is there any evidence anywhere that says the 450 engines had an unusually high CR. They certainly had more attention than the 400 engines as they have the larger sleeved 80mm plenums. Just wondering about the CR.
Cheers.
I thought there were a couple of bits different actually - the idler pulley - was that the funny little pump thing? I dunno where you'd put the intercooler, plus you'd need a shedload of pipe to get to the front of the nosecone and back if you put it there.
The plenum cover thing was correct though, and the throttle body too. It would take a bit of fettling to get it working, but with those brackets included, not too bad. There is one biggy missing though - you'd need to alter the ECU.
The plenum cover thing was correct though, and the throttle body too. It would take a bit of fettling to get it working, but with those brackets included, not too bad. There is one biggy missing though - you'd need to alter the ECU.
pwd95 said:
Does anyone know if a 450SE engine will accept a supercharger without a re build to alter the CR?
Basically is there any evidence anywhere that says the 450 engines had an unusually high CR. They certainly had more attention than the 400 engines as they have the larger sleeved 80mm plenums. Just wondering about the CR.
Cheers.
It's not the PSI ("BAR" for Brits) that causes predetonation, nor is it the CR alone. You can safely run boost even at 10.5:1, although you'd have to have reasonably low boost... perhaps 5 to 8 psi MAX! If you run good high octane fuel, and AIR To AIR intercooling you could get away safely with up to 7 or 8 PSI.Basically is there any evidence anywhere that says the 450 engines had an unusually high CR. They certainly had more attention than the 400 engines as they have the larger sleeved 80mm plenums. Just wondering about the CR.
Cheers.Compressing air (boost) makes the incoming charge hotter, thus increasing the pre-detonation likelyhood. OTOH, if you intercool your intake charge this can be eliminated somewhat.
If you try to run a roots style supercharger the best you can hope for is water cooled... the water cools the charge between the blower and the intake manifold. Since it's using your coolant system, about the best cooling you can hope for is 180-200 deg F,(not likely either) whereas if you use something like a turbo or a procharger the air-to-air intercooler becomes an option and now your intake charge is cooled to ambient temperatures. A procharger is also an easier bolt-on solution.
A couple of years ago I was checking out the procharger.com website and they had a graph detailing what PSI of boost you could safely run with whichever compression ratio you have. You might wish to look into this... http://www.procharger.com/intercooled.shtml (shows the boost/CR graph you can safely do)
Don't go with a roots blower... it may make more low rev boost, but you can't cool it nearly as well.
Hope this helps, good luck.
[edit] Actually I lie.. after reviewing procharger.com's boost/CR chart for the first time in a few years and assuming wedges are 10.5:1 (i think) you could push about 12 psi. You could NEVER get that performance with the style of blower a wedge "SX" uses!
Edited by Brap_Brap on Monday 29th March 02:50
You might want to check out these to sites :
http://www.sc-power.co.uk/
and
DPR (Dennis Priddle)
http://www.jagweb.com/aj6eng/superchargers.php
http://www.sc-power.co.uk/
and
DPR (Dennis Priddle)
http://www.jagweb.com/aj6eng/superchargers.php
10.5:1 was on the Rover P6 3500S - which ran on 5-star - most SDi's were 9.35:1 - and the stock wedges would be similar.
When you supercharge it's a bit like upping the CR accordingly. Air pressure is about 14psi so 6psi boost gives the equivalent of 20/14 * 9.35 = 13.35. This is assuming not much heat loss or intercooling (which will lose energy and hence pressure.) This is why the CR is commonly reduced.
Dennis said that the Sprintex screw-type blowers don't give as much heating as Roots blowers - as they are more efficient (less turbulence I suppose). So you can run up to 6psi boost without much fear of detonation, on high-octane fuel.
When you supercharge it's a bit like upping the CR accordingly. Air pressure is about 14psi so 6psi boost gives the equivalent of 20/14 * 9.35 = 13.35. This is assuming not much heat loss or intercooling (which will lose energy and hence pressure.) This is why the CR is commonly reduced.
Dennis said that the Sprintex screw-type blowers don't give as much heating as Roots blowers - as they are more efficient (less turbulence I suppose). So you can run up to 6psi boost without much fear of detonation, on high-octane fuel.
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