Gas research is just a different way to get the gas into the engine. No two companies share the same design, gas research uses a throttle body(s) to allow gas into the engine.SXC_302 said:i have a XC 302 and i was recommended not to gas research it as it was not good for older engine's such as the 76 cleveland.
is this correct?
10.5:1 comp is a walk in the park for LPG engines. Many years ago 13:1 was possible but now there is too much butane mixed into LPG for that.ESP said:Hi Guys,
Interesting chat about LPG.
I own a 1982 ESP V8 that has been running on straight LPG for 9 years.
It runs a crane 272 cam , 302 heads with 351 crank ( comp has been lowered to run approx 9.5 : 1 )
Impco 425 carby on Holley plate 1/2 inch phenolic spacer, a single B2 converter , Shaker scoop
LSD 3.23 gears in the rear
Tri Y Genies into twin 2 1/4 ( No petrol Tank )
C10 Auto 2300 stall
Crane Hi 6 Ignition and Coil Bosch Electronic Dizzy
This combo has given me 170 Rear wheel Kw and a quarter time of 14.3
I have also tried a brand new OHG 450 Gas carb but found it to be very difficult to tune and tailor. It ended up being quite boggy so I went back to the 425.
I also run a K & N Hi Flo filter inside the Shaker and have found it to work extremely well. I will also try the paper element to see if that makes a difference. Another post suggested that the paper filter was better suited to the 425.
I have found that most important feature of a good LPG motor is its vaccuum. You need to run a good vaccuum cam otherwise the car will run extremely rich at low throttle and will lean out dramatically at High revs. This is because the motor is the actual " sucker " of the fuel unlike Petrol engines where the fuel is forced in by the petrol pump.
I would be interested to hear from you guys about compression ratios for your LPG engines and the type of Head / Piston combos you are using. I have been recently told to keep the compression ratio to a max of about 9.5 : 1.
I was thinking of upping this to 10 : 1 but have been warned against it.
Apparently our current 50 : 50 LPG mix is not what it used to be.
Great talking with ya
You may find with LPG the pinging will improve, just make sure the dizzy is recurved and the whole setup is tuned by a good dyno tuner. Even with the small cam i'd say 10:1 should be OK.Chris Brooks said:They are using my thermoquadbase for this conversion. The thermoquad's flowed about 800cfm so the problem you mentioned about poor flow with 600 Holley's shouldn't be any problem for me.
One thing about compression is that the cam choice affects how much compression you can run be it on gas or petrol. 10:1 shouldn't be a major issue on just about any gas engine although mine will be on the edge as it's only got a Heatseeker stage 1 gas cam in it which is smaller than the stock clevo cam although it's a dual pattern cam. 258 degree intake and 264 degree exhaust seat to seat with only 0.440 thou lift.
It's no monster but it's better than driving a datto!! :s6: