JL Racing .12
#47
Originally Posted by blanks596
Do these engines need to be shimmed if planning to use 30%? if so, then by how much?
You may want to adjust the shims depending on nitro-content (see table) Nitro content: 16%/ 20% / 25%/ 30%
Head shims: 0.40mm / 0.40mm / 0.50mm / 0.60mm
Large tracks may require an extra 0.10mm shim to reach higher top speed and improved fuel consumption, but this will decrease acceleration slightly.
AFM
#49
Originally Posted by Team Kamikaze
The JL engines comes shimmed ready for 30% nitro already, meaning you don't have to do anything to the engine as far as preparation.
If you feel you need more top end with 30% Nitro, I would add one 0.10mm shim, for a total of 0.60mm.
AFM
#52
What about parts availability and prices: piston/sleeve....crank...bearings...plugs
AFM
AFM
#54
Originally Posted by blanks596
can someone explain the diff between ifmar and efra spec crankshaft and which is better?
Before November 2006 EFRA rules limited the crank's inner passage to a max. 7.0mm diameter with no chamfer at the oulet, and turbo scoop couldn't be connected to inner passage.
IFMAR had no limits to what could be done to crank.
After November 2006, EFRA has changed their rules to match IFMAR rules, so now they are the same, you can freely modify cranks in both formats.
As a side note: Some manufacturers like Picco don't belief that widening the inner passage will provide real benefits to an engine's performance, because you are restricted by rules to a max carb venturi of 5,5mm, and exhaust oulet is also restricted by rules to 5.2mm, so they just work on the turbo scoop to improve flow on IFMAR spec engines (and now EFRA).
Other manufacturers have inner passages up to 8.0mm wide (like Sirio for example)
It's a debatable technical situation...I guess both are right, depending on their engine design on crakcase volume.
AFM
#55
Performance Test
I tested the in car performance of the stock engine today. Wow it is very fast, and smooth. It also gets good fuel consumption. Not exactly sure how good, but it is noticeable. The engine was easy to break in, and it holds an idle very well. I tested with the Skyline VR12+. I did not see the need to try any thing else. This is definitely one of the fastest stock engines I have seen. Now it is time to test the mod version!
#56
Originally Posted by Grinder
I tested the in car performance of the stock engine today. Wow it is very fast, and smooth. It also gets good fuel consumption. Not exactly sure how good, but it is noticeable. The engine was easy to break in, and it holds an idle very well. I tested with the Skyline VR12+. I did not see the need to try any thing else. This is definitely one of the fastest stock engines I have seen. Now it is time to test the mod version!
AFM