KA24E improvements (pistons, etc)
#1
KA24E improvements (pistons, etc)
I'm fairly new to this but I've been doing some reading.
I'm building a 240sx for competition, it'll be fully gutted and stitch welded with a roll cage, I'm guessing somewhere around the 2400lb mark. I've got S13 Ohlins jdm suspension for it.
Now due to the rules I'm bound to the KA24E SOHC engine. I'm looking for more high end power and would like to move the usable power above 5500 rpm. I can't do anything too crazy due to strict rules. For example no SAFC or any other computers to control anything, no modifying/chipping the ECU, no ignition system modifications, etc
I've read that the Pre-Febuary built 1989 KA24E's have 9.1:1 compression vs the later 8.6:1. I also read somewhere about swapping pistons to get even higher compression? If I put the pistons from the 9.1:1 compression E motor into the 8.6:1 compression E motor what compression will I end up with. What about the opposite? Will this be a good idea given my restrictions?
Second is the MAF problem, I see upgrading to the N60 MAF will give me the higher powerband I want but I can't tune for it. I also read the thread about running the E60 MAF without tuning. I also noticed the S13 has the 60mm MAF, could I put a 70mm S14 KA24DE MAF onto this setup and have it work fine and give me what I want, possibly a compromise?
I'm going to be running a Cold Air Intake, 4-1 Headers for better top end power (Pacesetter maybe?) with 2.5" exhaust.
Is there any cheap nissan cam swap I can do that will help?
Other little things like the coolant bypass, vacuum lines and emission crap removal, A/C removal, SCV mod, grounding upgrade and I may do the modified catch can.
Any other little things I can do to improve that I'm missing? How does the EGR setup work, can I just yank that too?
I'm building a 240sx for competition, it'll be fully gutted and stitch welded with a roll cage, I'm guessing somewhere around the 2400lb mark. I've got S13 Ohlins jdm suspension for it.
Now due to the rules I'm bound to the KA24E SOHC engine. I'm looking for more high end power and would like to move the usable power above 5500 rpm. I can't do anything too crazy due to strict rules. For example no SAFC or any other computers to control anything, no modifying/chipping the ECU, no ignition system modifications, etc
I've read that the Pre-Febuary built 1989 KA24E's have 9.1:1 compression vs the later 8.6:1. I also read somewhere about swapping pistons to get even higher compression? If I put the pistons from the 9.1:1 compression E motor into the 8.6:1 compression E motor what compression will I end up with. What about the opposite? Will this be a good idea given my restrictions?
Second is the MAF problem, I see upgrading to the N60 MAF will give me the higher powerband I want but I can't tune for it. I also read the thread about running the E60 MAF without tuning. I also noticed the S13 has the 60mm MAF, could I put a 70mm S14 KA24DE MAF onto this setup and have it work fine and give me what I want, possibly a compromise?
I'm going to be running a Cold Air Intake, 4-1 Headers for better top end power (Pacesetter maybe?) with 2.5" exhaust.
Is there any cheap nissan cam swap I can do that will help?
Other little things like the coolant bypass, vacuum lines and emission crap removal, A/C removal, SCV mod, grounding upgrade and I may do the modified catch can.
Any other little things I can do to improve that I'm missing? How does the EGR setup work, can I just yank that too?
Last edited by tehf00; 06-05-2008 at 05:46 AM.
#2
Can you modify valves or do porting, honing, extruding?
Can you add bolt on's like aluminum drive shafts, aluminum flywheel, welded diffs?
Aluminum drive train parts can help pick up that re range a bit.
Can you add bolt on's like aluminum drive shafts, aluminum flywheel, welded diffs?
Aluminum drive train parts can help pick up that re range a bit.
#4
What kinda of valve modification? I can't do any porting, honing, extruding etc. The only thing I can do to the car is swap parts from the same manufacturer that I am able to use without modification.
There is no rule against bolt ons
From what I read the 4-1 give more higher end power while sacrificing lower end power compared to the 4-2-1
There is no rule against bolt ons
From what I read the 4-1 give more higher end power while sacrificing lower end power compared to the 4-2-1
#5
What kinda of valve modification? I can't do any porting, honing, extruding etc. The only thing I can do to the car is swap parts from the same manufacturer that I am able to use without modification.
There is no rule against bolt ons
From what I read the 4-1 give more higher end power while sacrificing lower end power compared to the 4-2-1
There is no rule against bolt ons
From what I read the 4-1 give more higher end power while sacrificing lower end power compared to the 4-2-1
If there is no rule against bolt ons you will want to look into an aluminum flywheel, and aluminum 1 piece drive shaft. Your going to need all the power you can get to the rear wheels. Possibly even look into aluminum rims as well.
Now in your case if you are allowed to bore the cylinder chamber I wouldn't even waste my time with sohc to sohc pistons. If you are allowed to bore you can look into the maximum bore of the KA block which is 91.5mm and go with a set of VG33E pistons which are 91.5mm. That will significantly raise your compression.
I would also look into thinner head gaskets.
If bolt ons aren't an issue you should look into an electric water pump as well as electric radiator fans.
Other than that I don't see very much more modifying for your situation, except for probably laser platinum spark plugs.
#6
4-2-1 it is
and I'm rebuilding the motor and doing the deck, I'll go with VG33E pistons if thats the best. Any idea what kind of compression that would yield?
Thanks for the info, I haven't heard of that yet.
So would the SOHC block I get matter vs 8.6:1 vs 9.1:1 or are they exactly the same other than the pistons and if I overbore it won't matter anyways?
and I'm rebuilding the motor and doing the deck, I'll go with VG33E pistons if thats the best. Any idea what kind of compression that would yield?
Thanks for the info, I haven't heard of that yet.
So would the SOHC block I get matter vs 8.6:1 vs 9.1:1 or are they exactly the same other than the pistons and if I overbore it won't matter anyways?
Last edited by tehf00; 06-05-2008 at 04:25 PM.
#7
4-2-1 it is
and I'm rebuilding the motor and doing the deck, I'll go with VG33E pistons if thats the best. Any idea what kind of compression that would yield?
Thanks for the info, I haven't heard of that yet.
So would the SOHC block I get matter vs 8.6:1 vs 9.1:1 or are they exactly the same other than the pistons and if I overbore it won't matter anyways?
and I'm rebuilding the motor and doing the deck, I'll go with VG33E pistons if thats the best. Any idea what kind of compression that would yield?
Thanks for the info, I haven't heard of that yet.
So would the SOHC block I get matter vs 8.6:1 vs 9.1:1 or are they exactly the same other than the pistons and if I overbore it won't matter anyways?
Now using the VG33 pistons a very enlarged piston with a crater style dish similar to the old NAPS-z style pistons. The advantage to using the VG33e piston is it's large piston size at 91.5mm. So you get much more compression and use alot more displacement to your advantage, not to mention the crater style dish can allow for much higher lift/duration cams.
PIC of VG33e piston
#9
The PDM cams- colt cams C404.H
http://www.pdm-racing.com/products/cam_corner.html
http://www.coltcams.com/html/tri_flo...logy/index.cfm
You have to mill the cam towers, or get solid lifters with adjustable valve lash.
http://www.pdm-racing.com/products/cam_corner.html
http://www.coltcams.com/html/tri_flo...logy/index.cfm
You have to mill the cam towers, or get solid lifters with adjustable valve lash.
Last edited by BigVinnie; 06-05-2008 at 11:55 PM.
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