question: Low CR vs. High CR for forced induction?

[Radar]

LPG from vapor injectors could be used in a high comp/boost setup.. After all freezing temps with 110octane. ( I think)

[Sam_Q]

LPG isnt 110 octane though, or atleast in Vic it isn't. It is a mixture of 4 gases for a octane 100RON

[Radar]

Ok even at 100RON wouldn't LPG be better to use than 98premo, due to the actual temp of the fuel going in?

[Sam_Q]

latent cooling they call it, yes you would think so although I have heard from a few reliable sources that the LPG injection guys are not getting as good a results as they should. It just doesn't sound right to me though as in theory it should work great.

It may also be of interest to some but the company Supagas here lets you buy pure propane directly from their refinery, 112RON all the way every time

[Shifty]

I will be interested to see how I go with my project.

I am running a static CR of 9.0:1 (factory) but in a turbocharged application. Most bikes are 12.0:1 and some even higher, so this is an effective 25% drop in static CR over a typical sportsbike which should give me significant overhead to run a little boost. I am planning to run ~5psi initially for around 150rwhp and 10psi to get around 190rwhp once it's sorted and I get used to it.

A realistic figure on the bike with a fully geared rider and pillion is about 410kg wet. With such a low weight and only 9.0:1 the effective static CR when extrapolated would be more like a car with 7.0:1 so I should get away with a decent amount of boost without an intercooler.

[Sam_Q]

so hold on you need to find out why the CR is so low stock, often it's not that simple. In stock form where does it make its power at what revs? how old is this bike? other spec?

[Sam_Q]

I dont know if I have mentioned it before but if anyone wants 20V pistons that can handle a heap of boost, are very light, easy to get and have a moderate CR then get the ACL race series pistons. They say 8.5:1 comp but its bullshit and contradictory. Using their own dish measurments I worked out around 10:1 with a silvertop head.

I know a guy who is using them with a T28 and I don't know if he is on here but he found even with no boost it's super responsive and nice to drive.