I searched around a bit and cant seem to find much.
I'm wondering what everyone's thoughts on how far I can rev my build out. I'm building a fresh 2.4 engine with a 2.3 oil pump swap, HO intake manifold, HO valve train, 35mm lifters, stainless valves, W41 cams, Brown top injectors and a stock but brand new bottom end.
So the W41 cams usually make power to ~7600-7800rpm right? Not much point in revving any higher than that, but I'm wondering how safe I am at these numbers? Could I rev to 8000rpm without worrying about my mains and rod bearings? I'd rather not have to build this thing again, haha.
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
I plan on revving mine out that high, I think the main reason people cringe at spinning an LD9 that high is the balance shafts moving twice the speed of the engine and the crappy oil pump. You have taken both of those issues out of the equation. I am no expert but it makes sense to me. I understand stroke makes a difference in that too, but we do not have that much more stroke than the 2.3 which is revved that high by a large number of people.
on the 2.4 i do not believe the W41 cams to make power that high. i only rev to 7k and around there i notice the power drop off. might be because of the difference in stroke but honestly i havent been on a dyno but the butt dyno feels it falling off.
gmanz24 (The Bash Whore) wrote:on the 2.4 i do not believe the W41 cams to make power that high. i only rev to 7k and around there i notice the power drop off. might be because of the difference in stroke but honestly i havent been on a dyno but the butt dyno feels it falling off.
see tim, thats what i thought. LOL
hmmm.. i forgot you are on stock rods... you MIGHT want to install ARP bolts just to be safe but i honestly dont see the rods holding out too many times at 8k.
crank will be fine, its frickn bullet proof...
With .430/222* cams I reved to 7500 and could have come more but power felt like it was falling off. My buddies 442 reves to 7800ish but is loosing power before then (based on feel alone).
Good to know, I appreciate everyone's help
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
whats your rod /stroke ratio?
I used a few online calculators and came up with a rod ratio of 1.51.
I'm not sure what the rod length is, the stroke is 94mm though. And I can't find the LD9 info thread....
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Transporter7220 wrote:I'm not sure what the rod length is, the stroke is 94mm though. And I can't find the LD9 info thread....
you did all this engine work and don't know the rod length? i thought you had the block at a few engine builders or whatever??
1.5 rod stroke ratio is absolute garbage. I don't think thats the right number....
rod length is 5.6125-5.6164 in according to the info I saved from Q4F library
DaFlyinSkwirl (Pj) v2.0 wrote:Transporter7220 wrote:I'm not sure what the rod length is, the stroke is 94mm though. And I can't find the LD9 info thread....
you did all this engine work and don't know the rod length? i thought you had the block at a few engine builders or whatever??
1.5 rod stroke ratio is absolute garbage. I don't think thats the right number....
Its not exactly a number I worry about having on the top of my head, or need for any of the work I'm doing, lol
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Transporter7220 wrote:DaFlyinSkwirl (Pj) v2.0 wrote:Transporter7220 wrote:I'm not sure what the rod length is, the stroke is 94mm though. And I can't find the LD9 info thread....
you did all this engine work and don't know the rod length? i thought you had the block at a few engine builders or whatever??
1.5 rod stroke ratio is absolute garbage. I don't think thats the right number....
Its not exactly a number I worry about having on the top of my head, or need for any of the work I'm doing, lol
Agreed! I wouldn't know if I hadn't done research to squeeze a bigger rod in there. To get a decent rod ratio of like 1.65 we would need a longer rod and to offset grind the crank a good deal loosing enough stroke to become a 2.3(still longer stroke that a factory 2.3 but with the smaller 2.4 bore that's how the numbers crunch) I ultimately decided it wasn't worth it. It was something like a 6" rod with a 3.63" stroke to get the 1.65. I cant remember what the rod came from I was going to use. Had to de-stroke so that there was enough meat on top of the piston and that was the thinnest tolerance recommended for the top of a forged piston.
Edited 1 time(s). Last edited Thursday, June 16, 2011 6:53 PM
EAGLE LD9 Rod length = 5.710" (145mm)
LD9 Stroke = 94mm
stock R/S = 1.54
I have no signiture
Could we use longer rods then the 2.3 rods if they were mahined to fit our crank and piston sleeves. If we use a shim or athicker headgassket?
I can't remember who's dyno graph it was...but the W41's stop making power around 7k or so. I plan on setting my rev limiter to 7200
Jason
99 Z24
LG0/LD9 for Life
10 Year Bash Veteren
Whalesac wrote:EAGLE LD9 Rod length = 5.710" (145mm)
LD9 Stroke = 94mm
stock R/S = 1.54
brian to the rescue!!! LOL thanks for that man.
for those interested... the 2.3 rod is 5.8 so not much longer but every little bit counts. i took .008 out of the centers of my "9.1" wisecos and chopped them all the way across completely flat to use 2.3 rods. .008 out of the center is nothing. hell ive seen people cut a BUNCH more than that out of 2.3 (stock even) pistons to fit them in an LD9 and they were fine. i cant believe nobody else has done this yet....
like i said... it takes a MASSIVE set of cams to get the NEED to go to 8000 rpm. larry dowty had like .450/.240's or something close and was shifting at 8k.
.510 / .280's would be sick.... hehe
(solid lifter of course)
-Z Yaaaa- wrote:
.510 / .280's would be sick.... hehe (solid lifter of course)
I vaguely recall years ago, one of the predominant Q4forums guys saying something about the air stagnating or something much past .450" lift on the 086...and you can see that when you look at flow numbers for these heads. More lift doesn't guarantee that much more flow. Duration and cam timing would certainly have a stronger impact.
I have no signiture
-Z Yaaaa- wrote:Whalesac wrote:EAGLE LD9 Rod length = 5.710" (145mm)
LD9 Stroke = 94mm
stock R/S = 1.54
brian to the rescue!!! LOL thanks for that man.
for those interested... the 2.3 rod is 5.8 so not much longer but every little bit counts. i took .008 out of the centers of my "9.1" wisecos and chopped them all the way across completely flat to use 2.3 rods. .008 out of the center is nothing. hell ive seen people cut a BUNCH more than that out of 2.3 (stock even) pistons to fit them in an LD9 and they were fine. i cant believe nobody else has done this yet....
like i said... it takes a MASSIVE set of cams to get the NEED to go to 8000 rpm. larry dowty had like .450/.240's or something close and was shifting at 8k.
.510 / .280's would be sick.... hehe (solid lifter of course)
SO what you are saying is that when i finally get mine together I need to rev out to 8000RPM?? Cant wait to finally hear my .430/240* cams. Only had them for how long??
i rev mine out to 7500 just for a better rpm in next gear but it only has ever made power to around 6700. ho cams.
