L24 Vs L26 Vs L28 Vs L31
10-27-2002, 05:48 AM
#1
Guest
Posts: n/a
L24 Vs L26 Vs L28 Vs L31
ok so here's a fun question to get everyone thinking and commenting.
I currently have a L28 in my 240z. I used to have an L24 and that thing revved like crazy the L28 doesn't rev as friendly but it shells out the torque.
In my opinion the L28 should have much more power than the l24 therefore go quicker. But what about the High Comp E31 head on an L24 block????????? My L28 has the E88 head and 10:1 comp ratio.
I was thinking about working it a little more maybe slightly larger cam and the Diesel crank.
My main question is this does an overbored L28 to 3.1L go harder or what? Do you loose revability when u dump in an L28 and if so is it cause the stroke is longer????
What if you shove the 240k rods in there what difference does that make???
I know a guy with an L28 turbo , 240k rods, GTR pistons and rings and he puts out 200kw+.
I just basically wanna hear a debate over what's best and what are the pro's and con's. I would have always thought bigger engine = more power and go faster.
Would anyone quote an L28 with 240z SU's 10:1 Comp Ratio , Electronic Ignition E88 head, 280zx Valves. Slight Duration Cam, up around 200hp+????????? That's what I'm running now and the last owner said it was around 200hp but I'm not so sure.
Gavin,
Melbourne
Australia
1972 Datsun 240z
I currently have a L28 in my 240z. I used to have an L24 and that thing revved like crazy the L28 doesn't rev as friendly but it shells out the torque.
In my opinion the L28 should have much more power than the l24 therefore go quicker. But what about the High Comp E31 head on an L24 block????????? My L28 has the E88 head and 10:1 comp ratio.
I was thinking about working it a little more maybe slightly larger cam and the Diesel crank.
My main question is this does an overbored L28 to 3.1L go harder or what? Do you loose revability when u dump in an L28 and if so is it cause the stroke is longer????
What if you shove the 240k rods in there what difference does that make???
I know a guy with an L28 turbo , 240k rods, GTR pistons and rings and he puts out 200kw+.
I just basically wanna hear a debate over what's best and what are the pro's and con's. I would have always thought bigger engine = more power and go faster.
Would anyone quote an L28 with 240z SU's 10:1 Comp Ratio , Electronic Ignition E88 head, 280zx Valves. Slight Duration Cam, up around 200hp+????????? That's what I'm running now and the last owner said it was around 200hp but I'm not so sure.
Gavin,
Melbourne
Australia
1972 Datsun 240z
10-28-2002, 08:29 AM
#2
The Evil Twin
Join Date: Mar 2001
Location: Seattle, WA
Posts: 9,294
Re: L24 Vs L26 Vs L28 Vs L31
The L28 is a longer stroke and that usually means it will not free rev as fast. The added torque makes it rev up faster while pulling the car. It should defiantly have more power than the L24. Even a stoker crank can rev up very high. I guess its mainly dependant on your head work. If your intake and exhaust is very well done and you head is too, then it should have no problem at higher rpms.
To get a 3.1 engine you have to not only bore it but stroke it. If you do a 3mm overbore (which is a safe limit) then you'll have a 3.0 but with the same stroke as the L28 because you didnt' change the crankshaft.
Changing pistons is a way to change your compression ratio, but not all Nissan pistons are the same height. I dont' know all the details on that. Just use the later 280zx block F54 with flat top pistons and then whatever head you have now and you'll increase your compression. (unless that's already what you have)
Your engine might feel like 200hp, but it probably doesn't have that kind of power at the wheels. I'd say maybe 150hp. I saw a car on the dyno with what you've got only he had tripple webbers. He dynoed at 151hp at the wheels. Truthfully, most people with n/a engines don't dyno all that high but they sure do get some really fast quarter mile ETs with their light weight 240Z.
When I do a rebuild, I was thinking of just boring the engine and putting in new pistons from maybe a 240SX or something. That'll give me an L30 but with the same stroke I'm used to. I'll just re-tune the AFM to add a little more fuel for the increase displacement. it'll probably add another 10hp and maybe 15 lbs of torque.
To get a 3.1 engine you have to not only bore it but stroke it. If you do a 3mm overbore (which is a safe limit) then you'll have a 3.0 but with the same stroke as the L28 because you didnt' change the crankshaft.
Changing pistons is a way to change your compression ratio, but not all Nissan pistons are the same height. I dont' know all the details on that. Just use the later 280zx block F54 with flat top pistons and then whatever head you have now and you'll increase your compression. (unless that's already what you have)
Your engine might feel like 200hp, but it probably doesn't have that kind of power at the wheels. I'd say maybe 150hp. I saw a car on the dyno with what you've got only he had tripple webbers. He dynoed at 151hp at the wheels. Truthfully, most people with n/a engines don't dyno all that high but they sure do get some really fast quarter mile ETs with their light weight 240Z.
When I do a rebuild, I was thinking of just boring the engine and putting in new pistons from maybe a 240SX or something. That'll give me an L30 but with the same stroke I'm used to. I'll just re-tune the AFM to add a little more fuel for the increase displacement. it'll probably add another 10hp and maybe 15 lbs of torque.
10-28-2002, 03:22 PM
#3
Guest
Posts: n/a
