I am going to be rebuilding an LD9 come this spring. I'm trying to decide which head to use. I know the 086 is a flow king and has the bigger valves and stuffer springs and all, plus bumps the 9.5cr to 11.25:1.
What I'd like to know is what is better for boost and what is better for torque? I don't plan on drag racing, I plan on driving this thing every day like I do and taking it to weekend autocrosses when I can, so I want torque to place priority.
I either want to swap to the 086 and get like 7.5:1 pistons to lower the cr back to stock OR do head work on the 2.4L and go with 9:1 cr.
I would really like to go 086 as it seems cheeper as the work is allready done that i would have to do to the 2.4 cept will flow better than a 2.4 ever will. I just want to make sure it'll make comparable torque. I'd like to see 250hp and 250ft lbs of torque to the wheels.
Also does anyone know where i could get a 7.5:1 cr piston?
Thanks in advance,
- Paul
Paul look around in this forum & the performance one as this seems to be a hot topic right now. I'm currently building a turbo 2.4 with the 086 head and I agree with you about the difference in the flow of the heads, however I choose the 086 because I have a goal of 500 - 550 hp at the flywheel and I know I'll never reach that with the 2.4 head no matter how much port work is done to it. Now since you stated your goal is more tq and you want to make 350 hp/tq you can do that with a ported 2.4 head with HO cams, valvesprings, 2.3 oiling system swap and a T3/To4b 57 or 60 trim turbo.
2000 Z24 5spd header & catback for now.
First i'd like to thank you for answering all my little questions lately.
As for the motor, my goal is 250hp/tq(not sure if you mis typed or not) and by porting you mean all I have to do it get a port job on the head no valve work? Also how indepth is this port job? As for the cams, will the HO exaust cam with the 95 intake cam do?
Thanks again,
- Paul
Paul Yannacopoulos wrote:First i'd like to thank you for answering all my little questions lately.
As for the motor, my goal is 250hp/tq(not sure if you mis typed or not) and by porting you mean all I have to do it get a port job on the head no valve work? Also how indepth is this port job? As for the cams, will the HO exaust cam with the 95 intake cam do?
Thanks again,
If you port, you have to get larger valves.
The H.O. cam is too large to run on stock springs and would require HPT or a standalone to manage fuel delivery.
I personally am biased to the 086 head, but is by no means necessary for the power you want with a turbo or m62 charger. I built my motor with the intent that I can upgrade to boost when I want to, and still be be plenty quick N/A. The 086 head just seems too easy not to do (just expand and drill new water passages and your done).
7.5:1 would have to be custom. Ross should be able to make you 8.5 or 8:1 pistons then add reliefs to lower the compression the rest of the way (as well as providing support for really high lift). I don't know, however, how much material would be left in the piston between the surface of the piston in the combustion chamber and the wrist pin.
If you were wanting 9:1 with an 086 head, I calculated the piston needed, should be 7.8:1
Paul Yannacopoulos wrote:I am going to be rebuilding an LD9 come this spring. I'm trying to decide which head to use. I know the 086 is a flow king and has the bigger valves and stuffer springs and all, plus bumps the 9.5cr to 11.25:1.
What I'd like to know is what is better for boost and what is better for torque? I don't plan on drag racing, I plan on driving this thing every day like I do and taking it to weekend autocrosses when I can, so I want torque to place priority.
I either want to swap to the 086 and get like 7.5:1 pistons to lower the cr back to stock OR do head work on the 2.4L and go with 9:1 cr.
I would really like to go 086 as it seems cheeper as the work is allready done that i would have to do to the 2.4 cept will flow better than a 2.4 ever will. I just want to make sure it'll make comparable torque. I'd like to see 250hp and 250ft lbs of torque to the wheels.
If all you want is 250whp, you could probably pull that
n/a using the 086, HO cams and a decent tune.
Dale Young wrote:Paul look around in this forum & the performance one as this seems to be a hot topic right now. I'm currently building a turbo 2.4 with the 086 head and I agree with you about the difference in the flow of the heads, however I choose the 086 because I have a goal of 500 - 550 hp at the flywheel and I know I'll never reach that with the 2.4 head no matter how much port work is done to it. Now since you stated your goal is more tq and you want to make 350 hp/tq you can do that with a ported 2.4 head with HO cams, valvesprings, 2.3 oiling system swap and a T3/To4b 57 or 60 trim turbo.
I believe a you can make 500bhp using a 2.4 head. In fact, i believe it can be done on less that 20 psi of boost.
Brian Whalen wrote:
If you port, you have to get larger valves.
The H.O. cam is too large to run on stock springs and would require HPT or a standalone to manage fuel delivery.
If you get your head ported, you do
not have to use larger valves.
HO cams are
not too large to run on stock valve springs and and do
not require HPT or a standalone to run.
- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.
Thanks for the help guys,
I'm thinking of using the 086 with a cometic head gasket that is .074" which should change the cr to 10.5:1 then i can use off the shelf 8.5:1 pistons to get it back down to stock 9.5cr, peftect for boost. The main reason i was against it was because of the compression but now since its at a decent level the rest can be sorted out with tunning.
I have one more thing, I searched around and i've come up with a few descripencies with sizes for the engine, could someone clairify my numbers for a 98 ld9,
LD9 LD9 w/086
Bore 3.54 3.54
Stroke 3.7 3.7
Head cc's 60 48
Gasket Thickness 0.047 0.047
Deck Height 0 0
Dish or Valve Pocket [-] or Dome [+] cc's: -2.6 -2.6
Piston Volume 36.41649381 36.41649381
Piston Volume (cc) 596.7594147 596.7594147
Gasket Volme (ci) 0.462587894 0.462587894
Gasket Volme (cc) 7.58045743 7.58045743
Compression Volume 70.18045743 58.18045743
(Head cc's + Gasket Thickness+valve pocket)
Compression Ratio 9.503213524 11.25704233
Thanks again
- Paul
Those numbers are about the same as what I get.
cool thanks, i'll keep using them for calculations. seeing how i can get 9.5:1cr with a head that flows better than a ported 2.4, and has bigger valves and stronger valves springs, and to get one will be waay cheeper than a ported 2.4 head, It looks like that's the route I will take.
086 here i come!
Thanks for the help guys
- Paul
out of curiosity is there 086 stock flow charts vs 2.4 stock flow charts?
R.I.P. Brian Klocke, you will never be forgotten
Quad 4 Head flow rates - CFM
Flowed at Peak Performance - Fenton, MO - 636-671-3300
Lift 0.100 0.200 0.300 0.350 0.400 0.450 0.450 0.500 0.600 0.650
(with exhaust pipe)
Ported 086 (Kevin Davis Exclusive)
Intake 84.2 164.8 226.7 250.2 269.3 286.1 xxxxxxxxxxxxxxxxx
Exhaust 131.4 139.7 181.6 194.3 202.5 207 237.3
Stock 086
Intake 73.3 149.2 221.7 250.8 267 274.6 xxxxxxxxxxxxxxxxx
Exhaust 57.1 125.1 167.7 176.2 180.3 183.2 205.6
Stock 456
Intake 77 156.2 222.6 248.7 261.4 265 xxxxxxxxxxxxxxxxx
Exhaust 67.8 135.5 164.5 168.3 170.8 172.9 197.7
Stock 955
Intake 96.7 164.8 230.2 234.2 239.3 240 xxxxxxxxxxxxxxxxx
Exhaust 68.2 127.7 149.5 151.9 153.8 160 170.8
Does this help, which is the 2.4 head casting?
- Paul
None are 2.4 head. 456 is a 95 2.3, 086 is LGO and LD2, 955 is 87-89 LD2
Gilles
2.3 Ho
Gilles...can I have your permission to put you on my "Phone A Friend" list if a Quad4 question came up?
I just think its hillarious you got an answer for everything and its never I'll have to look it up!!!
We need to start a thread titled Stump Gilles
hahahaha
I don't know erverything about the Quad 4 but I know alot.
Nobody never tried to get me.
Gilles
2.3 Ho
