I searched but couldn't find anything about shorter forged rods for the ld9. Do they even exist? I originally wanted to turbo my car this summer, but unfortunately I spun a rod bearing and cracked a piston, so I am replacing the entire bottom end.
The reason I am asking about shorter rods instead of pistons, is because I want to swap the 086 head on my 2.4L, and stay N/A for now then when I decide to, replace the pisons with forged 9:1 CR ones for boost.
I really don't want to buy custom 8.5:1 CR pistons to lower the compression to 10:1, just to have them replaced again with 7.5:1 CR(assuming 7.5:1 CR pistons are possible).
I keep going through the calculations, and it seems that the rods would need to be about .07" shorter to lower the compression from 11.4:1 to 9.7:1. Any useful information would be appreciated. Thanks.
Mmmmm if you get 9:1 compression pistons your final compression with a 086 head should be at about 10.5:1 or so . . . .
Also, custom rods will not only cost you an arm and a leg since you would only be buying 1 set of them... but it would prolly take a very long time to get them made as well....
Thanks guys. Thats pretty much what I figured. In any case, approximately how much boost could I run with 10.5:1 CR and a possible water/ alcohol injection kit on 93 Octane? Possibly 10-15 max?
Also, not to turn this into a chatroom, but did anyone see the 2700Hp Camaro in this month's Car Craft. Thats just sick.
plus you dont want shorter rods , it would change the way the pistons hit the walls of the cylinders , and cause wear issues
if anything you want a slightly longer rod
like they said itll cost more , then its worth
you do have 3 options , thicker head gasket , port the combustion chamber to increase the cc volume which will drop the compression , or pistons
also you can do all 3 , or any combo of them
the amount of boost you can run , is only limited to how well you can tune the motor
alot of the drag cars run over 11 to 1
Karo the 9:1 2.4 pistons will give 10:1 with an 086 head, I keep seeing on this board where an 086 head on an otherwise stock 2.4 short block yeilds 11.5:1 from 9.5:1 stock. If what you say is true then great I won't have to wait for custom 8.5:1 cr pistons to get 10.5:1 with the 086 head.
Brian with 10.5:1 static cr on intercooled boost with water/meth injection and spot on tuning I would think 15 - 18 should be possible if you keep the inlet air temps low or if you get the right cams to bleed off cylinder pressure.
2000 Z24 5spd header & catback for now.
Thanks guys. That's all great information. I have a question for you Dale: you mentioned cams with a shorter duration. I already have the "secret" cams, so couldn't I just get adjustable cam gears (or drill a new hole in the cam gears I have now) to advance or retard the timing accordingly to essentially do the exact same thing as getting new cams? I'm sorry if that sounds like a newbie question.
Mike Karas had shorter rods from Eagle in his built 2.4 motor. They were only a tad bit shorter than stock tho.
275hp & 306tq - 1999 2.2 ohv
13.2 @ 108 mph
-1996 2.4 liter + Turbo + Built motor + Torco + More boost = Lots o' Power
-2000 Mustang GT + 2004 Cobra motor, Whipple 2.3 supercharger,
built rear-end,Dodge Viper spec T56 6 speed, bolt-ons = wheelies at the track!!!!!
Oh yea, the rods were for a Honda motor, I think it was the H22. At the time when he was starting to build the motor, there was not a company who offered forged 2.4 rods at a resonable price. So he ordered the Honda rods from Eagle and did a little bit of machining to the crank and/or rods.
275hp & 306tq - 1999 2.2 ohv
13.2 @ 108 mph
-1996 2.4 liter + Turbo + Built motor + Torco + More boost = Lots o' Power
-2000 Mustang GT + 2004 Cobra motor, Whipple 2.3 supercharger,
built rear-end,Dodge Viper spec T56 6 speed, bolt-ons = wheelies at the track!!!!!
a smaller duration cam will not decrease cylender pressures it will increase it. and as for the shorter rods, depends on what the rod angle is, but you'd be better off with longer rods and just getting custom pistons (longer rods to move the wrist pin up as far as you can go without getting into the oil rings in the piston) this will help stabilize and lighten the pistons....
_______________________
** Flat Broke Racing Inc.**
We have Eagle forged rods in stock for a price less than $300. For the 2.4L and the 2.2L Ecotec.
-Aaron
www.TurboTechRacing.com
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