willgbr
New Member
I dont think there are many places that can do it properly full stop are they?
Headgasket Advice
- Thread starter willgbr
- Start date
red reading
Active Member
i will get some piccy's for you stu as it was a work of toilet your old block:evil:
stumo
Active Member
we shall see.8)
P
pulsarboby
Guest
lol that these guys arent stuey;-)
have met them and they are serious car fanatics who have done an immense amount of reseaerch and work
so fair play to them
plus theyve designed my website, and will be forever helping me out when i keep fooking it up:lol::lol:
Fusion Ed
Active Member
I just thought I would share this with you. http://www.fs.isy.liu.se/~larer/Projects/main.html
This research is not new and is backed up by other similar areas of research, but in essence, in order to determine the best compression ratio for an engine research must be undertaken to establish the point of PPP (peak pressure position) vs compression ratio/vs fuel to be used.
For an engine to develop the best amount of torque and therefore power under all operating conditions PPP occurs at about 17deg ATC. However the ignition advance to achieve this can vary greatly depending on engine load/rpm etc (hence why we used 3d ignition maps).
Problems can occur when the compression ratio is such that firing the ignition at an optimal point to create PPP @ 17deg ATC causes the fuel to spontaneously ignite, forcing you to have to retard ignition and as a result loose efficiency and power, it is at this point that CR needs to be dropped. Conversely you may find that you are able to up the compression ratio to optimise the engine design for a given spec to enable more power from it if 17deg ATC is easily achieved without approaching upon knock.
Ed
Let us know how you get on, I'm interested to know what is needed to use this effectively on an R.
stumo
Active Member
I've not read the link yet but it's really a suck-it-and-see, even if you've got all the equipment.
Unless anyone has experience of a R running E85 and producing upwards of 500hp then it's pie in the sky what comp you can get away with.
You might be able to make an educated guess but without trying stuff (like using the gasket he's already got) you're not going to know if it's going to work or not.
stumo
Active Member
well after building the engine 3 or 4 times (i forget how many) looking for the problem (and finally finding it after using ceramic sealer....it didn't work but that's another story) the comp ratio ended up somewhat higher than i had originally planned.
It still wasn't knock limited and i think i could have run with it even higher (i only got as far as running it at 1.6Bar but it was pretty quick)
It still wasn't knock limited and i think i could have run with it even higher (i only got as far as running it at 1.6Bar but it was pretty quick)
Fusion Ed
Active Member
I have never had problems with say running 1.6 bar on 1.2mm gaskets or so on a pulsar, but they do get really sensitive above this boost level I have found. One reason I don't like it as much is people thrash pulsars, sometimes put in wrong fuel etc etc and the margin for safety is so much smaller.
Me too - I want to know how much of the problems people predict are just scaremongering, and how much is truth. Have you done anything special to run it on E85? I'm unsure about what is and isn't compatible with a polar fuel instead of a non-polar one; what fuel pump are you using (I'd read that it needs to be different because ethanol is conductive whereas petrol isn't).
Jim, the other thing I noticed in that link that was posted in your thread on E85 was that they were carburetted engines, not injected.
Rishi
Still waiting on some shims!
I personally used an HKS 1.2mm Gasket and had it built to 8:5:1..
But if you are using E85 then you should manage to get away with 8:8:1 quite happily.. I'm sure some of these guys will have some more detailed input into this..
If you really want a thicker gasket then I'd use either the HKS 2.0mm or the Cosworth 1.8mm.. Wouldn't bother with the Cometic.. They've been associated with too many failures..
But if you are using E85 then you should manage to get away with 8:8:1 quite happily.. I'm sure some of these guys will have some more detailed input into this..
If you really want a thicker gasket then I'd use either the HKS 2.0mm or the Cosworth 1.8mm.. Wouldn't bother with the Cometic.. They've been associated with too many failures..