low boost/high compression
#1
low boost/high compression
Hi Folks,
Sorry if this has been done before (feel free to provide the link )
Here in Australia, we have a class for basically stock sports cars that run on semi-slicks. Cams, pistons etc are free - stock inlet manifold, original head, block and crank - they can be modified but must remain basically what was in the car when it was sold by the manufacturer.
I currently have 11:1 pistons, larger valves, 276 Deg cams and a light flywheel with Exedy clutch. Oh and a Maruha head gasket.
Some of the other guys in the class run supercharged Lotus Elise/Exiges with high compression and they rock!
What is the general consensus of the forum about using an SE manifold/turbo on 6 - 7 lbs boost with the high comp pistons? Don't want to undo the work I have already done..
Sorry if this has been done before (feel free to provide the link )
Here in Australia, we have a class for basically stock sports cars that run on semi-slicks. Cams, pistons etc are free - stock inlet manifold, original head, block and crank - they can be modified but must remain basically what was in the car when it was sold by the manufacturer.
I currently have 11:1 pistons, larger valves, 276 Deg cams and a light flywheel with Exedy clutch. Oh and a Maruha head gasket.
Some of the other guys in the class run supercharged Lotus Elise/Exiges with high compression and they rock!
What is the general consensus of the forum about using an SE manifold/turbo on 6 - 7 lbs boost with the high comp pistons? Don't want to undo the work I have already done..
#8
Boost Pope
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Since he already has an assembled, running engine which is set for 11:1 CR, the options as I see them are:
This isn't a path often traveled by members on this forum, as most of us (myself included) are either too lazy to rebuild the engine with aftermarket pistons, or if not, have specifically built to lower CR, not to raise it. Still, it sounds like a potentially very interesting project.
colster3, pardon my ignorance (and perhaps it's a cultural-lingustic barrier at play) but what is "an SE manifold/turbo"?
- Do nothing.
- Add turbo at low boost.
- Add turbo at high boost, also completely rebuild engine for low compression.
This isn't a path often traveled by members on this forum, as most of us (myself included) are either too lazy to rebuild the engine with aftermarket pistons, or if not, have specifically built to lower CR, not to raise it. Still, it sounds like a potentially very interesting project.
colster3, pardon my ignorance (and perhaps it's a cultural-lingustic barrier at play) but what is "an SE manifold/turbo"?
#9
More cylinders and well flowing heads are always a plus, but we're discussing a miata setup here, so who cares about other stuff.
I think it will be a GREAT setup for OP on e85. You got a ton of response and potential to make good power with little boost, and the e85 will definitely put a huge cushion on heat/det. I'd be worried about rods though. With high compression and even low boost stock rods will be on thin ice.
I think it will be a GREAT setup for OP on e85. You got a ton of response and potential to make good power with little boost, and the e85 will definitely put a huge cushion on heat/det. I'd be worried about rods though. With high compression and even low boost stock rods will be on thin ice.
#10
Joe you have a good point and so does 18psi. If you are running stock rods then I wouldn't temp a high compression motor even on low boost. Just to do rods you would be doing a rebuild so at that point you might as well try and drop to some thing a bit lower like 10:1 or 9.5:1. I did 9.5:1 and got great numbers out of it on a 16g with 20psi. Made 350whp and 305wtq. Had full boost by 3700-4000.
#11
Thanks for the opinions guys,
Joe - the factory turbo Miata here in Australia was badged as an SE to differentiate from a locally produced SP - aftermarket kit fitted by the unofficial competition arm here.
The manifold is a Mazda part and the turbo (not familiar with size/ID numbers etc) is fairly small.
My concept was exactly as 18PSI had suggested. Great response, a bit more power and a couple of spots further up the grid. By the way, forgot to mention that the engine has Carillo rods, and ARP stud kit for mains and cylinder head...
Joe - the factory turbo Miata here in Australia was badged as an SE to differentiate from a locally produced SP - aftermarket kit fitted by the unofficial competition arm here.
The manifold is a Mazda part and the turbo (not familiar with size/ID numbers etc) is fairly small.
My concept was exactly as 18PSI had suggested. Great response, a bit more power and a couple of spots further up the grid. By the way, forgot to mention that the engine has Carillo rods, and ARP stud kit for mains and cylinder head...
#18
Hi Folks,
Sorry if this has been done before (feel free to provide the link )
Here in Australia, we have a class for basically stock sports cars that run on semi-slicks. Cams, pistons etc are free - stock inlet manifold, original head, block and crank - they can be modified but must remain basically what was in the car when it was sold by the manufacturer.
I currently have 11:1 pistons, larger valves, 276 Deg cams and a light flywheel with Exedy clutch. Oh and a Maruha head gasket.
Some of the other guys in the class run supercharged Lotus Elise/Exiges with high compression and they rock!
What is the general consensus of the forum about using an SE manifold/turbo on 6 - 7 lbs boost with the high comp pistons? Don't want to undo the work I have already done..
Sorry if this has been done before (feel free to provide the link )
Here in Australia, we have a class for basically stock sports cars that run on semi-slicks. Cams, pistons etc are free - stock inlet manifold, original head, block and crank - they can be modified but must remain basically what was in the car when it was sold by the manufacturer.
I currently have 11:1 pistons, larger valves, 276 Deg cams and a light flywheel with Exedy clutch. Oh and a Maruha head gasket.
Some of the other guys in the class run supercharged Lotus Elise/Exiges with high compression and they rock!
What is the general consensus of the forum about using an SE manifold/turbo on 6 - 7 lbs boost with the high comp pistons? Don't want to undo the work I have already done..
Hey mate where are you from?
Im from newcastle (nsw) running an e85 powered 10.5:1 NA, going boosted soon.
Dann