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Getting 120whp out of L20B


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I have seen a single cam ka pass by me for $50 and a double cam for $200 recently and with my friend bugging the crap out of me to just grab a KA and put it in im still set on building a L20B for some reason.

 

This is my 4th car over the last couple of cars and out of all of them it was my first 12a carbed rotary 83 RX7 that treated me the best. It wasnt the quickest but it was agile and when something broke down it was mechanical and easy to get to.

Second car was a FD pushing somewhere over 200whp and tho it was fast it was the car that ruined my life (seriously)

Just before the 510 I was racing a little miata that was only pushing 115whp but was still a blast.

 

I realize that a L20B is about 80-90whp stock so 120 is a pretty big goal but I just want to be have something that still has a little "oomph". If the condition of my car had been terrible when I purchased it I would just throw the KA in and be done with it but because its still so original I would kind of like to keep it old school.

 

I have been reading and reading but not knowing much about the L series motors im just getting confused (ill still keep reading lol). So my question is would I be spending a stupid amount of money to get around 120whp?

 

After driving rotary for most of my car ownership im not worried about MPG (Rotary=Terrible MPG and the need to consume 91-94 octane) so I was thinking a high compression L20B with dual side drafts.

 

Again, I dont know much about these motors and im still juggling between ideas. Just love the sound of carbs and the idea of keeping it old school.

 

If you have any links to a good build or thread for this I would love a link!

 

Thanks again guys and sorry for asking what I feel is probably a real common question.

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it depends on your idea of "stupid amount of money" 

 

are you sure you have an l20b? because you say its "so original" and originally the 510 came with an l16 

 

from what ive been reading and researching ( gonna be rebuilding my l20 soon) get your hands on some 1mm overbore  l18 pistons to bump the compression up a little bit and bump displacement up from 1952 cc to 1998cc port and polish the head with a good cam and a single sidedraft or su carbs  im not sure if this will get you close to 120hp at the wheels but it will net you a considerable gain over stock for imguessing about 1500 bucks? maybe 2k? 

 

your friend has a point for the amount of money you will be spending on an l series to get in the 140hp ball park might as well just drop a ka in it that makes that kind of hp stock 

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Get a Z22 block and put an L series head on it. You have an instant 10 hp. Cam and R-1 carbs you should get another 15 hp.
 
I would hone the block to 89mm. Install KA24E* (edit) (used or new) pistons on the Z22 or L20B rods for a 2.3 liter motor. L20B timing cover and timing chain and parts. U67 head. (cheap and plentiful) L16/18 exhaust manifold. Make an intake for R-1 carbs. This would be close to 120 hp and if a cam was added....?
 
Byron from The Ream had  a 2.2 liter L motor with cam and side drafts 132RWHP!!!!
 
This was his EFI set up. Only made 5-6 more HP than the carbed.
DynoRun2007ByronsLZ22.jpg

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Guest 510kamikazifreak

The LZ frankinstein is the best bang for the low buck

Junkyard parts,and they are plenty peppy

Just dont forget to drill out the water passages it the Z22 block..

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yeah you can get 120 to the wheels with an l20. 

 

thats on the far end of the L20 though. its going to be to that edge of not being streetable. 

 

going with a z22 bottom end, you have a little more displacement to play around with, and ive seen 155 at the wheels from this combo. 

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Guest 510kamikazifreak
It's very easy to get that kind of power from an L20B...Just add more air. Turbosupercharging has been around since the 60's and earlier.

 

 

Not cheap tho

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Get a Z22 block and put an L series head on it. You have an instant 10 hp. Cam and R-1 carbs you should get another 15 hp.

 

I would hone the block to 89mm. Install KA254E (used or new) pistons on the Z22 or L20B rods for a 2.3 liter motor. L20B timing cover and timing chain and parts. U67 head. (cheap and plentiful) L16/18 exhaust manifold. Make an intake for R-1 carbs. This would be close to 120 hp and if a cam was added....?

 

Byron from The Ream had  a 2.2 liter L motor with cam and side drafts 132RWHP!!!!

 

This was his EFI set up. Only made 5-6 more HP than the carbed.

DynoRun2007ByronsLZ22.jpg

 

 

^I'm gonna build a 2.3 block for my cammed U67 head and R1 carbs!!!

 

Hope to make a nice 140+ whp

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I dunno guys, I've spent 590$, which includes:

 

1 Eaton M62 supercharger, completely rebuilt and ported

Custom mounting brackets

Custom intercooler and piping, all silicone couplers and T-bolt clamps

6 DSM 450cc/min Injectors

2 fuel rails (I fucked up one of 'em)

1 ITB, dual-plenum intake manifold (not quite finished, need to get it decked and then it'll get bolted up

New RB25DE lightweight flywheel

New 350Z clutch

FS5W71C transmission

 

I already have a nice header on the car, but it will be getting a new flex joint and v-band clamp, and the flange will get machined flat again. I will be up and running 8.5lbs of intercooled boost by mid-april.

 

I'll be needing to shorten the driveshaft and build a new transmission crossmember, but that's an evening's work.

 

Turbo or supercharging an engine doesn't have to be expensive. Hell, the whole rebuild, including porting the head, boring the block, new pistons, rings, bearings, seals, gaskets, damper, ect. for my L28, was 810$

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I know this is an engine thread but I have not read any one talk about changing the rear end gear and adding a five speed. Unless you are on the freeway alot I think this would make for a peppy ride. I did this in my El Camino, and thinking about it for my wagon. Hopping up the engine with too aggressive a cam moves the power range up in rpm. Fun for a while, but sometimes the noise is too much. Yes... maybe I am just getting too old.

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Get a Z22 block and put an L series head on it. You have an instant 10 hp. Cam and R-1 carbs you should get another 15 hp.

 

I would hone the block to 89mm. Install KA254E (used or new) pistons on the Z22 or L20B rods for a 2.3 liter motor. L20B timing cover and timing chain and parts. U67 head. (cheap and plentiful) L16/18 exhaust manifold. Make an intake for R-1 carbs. This would be close to 120 hp and if a cam was added....?

 

Byron from The Ream had  a 2.2 liter L motor with cam and side drafts 132RWHP!!!!

 

This was his EFI set up. Only made 5-6 more HP than the carbed.

DynoRun2007ByronsLZ22.jpg

89mm Cant those be found in the L2.8 z motor also ?? maybe a little cheaper than the ka ?

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Turbo or supercharging an engine doesn't have to be expensive. Hell, the whole rebuild, including porting the head, boring the block, new pistons, rings, bearings, seals, gaskets, damper, ect. for my L28, was 810$

That's about $3600+ Canadian.....lol

 

 

I know this is an engine thread but I have not read any one talk about changing the rear end gear and adding a five speed. Unless you are on the freeway alot I think this would make for a peppy ride. I did this in my El Camino, and thinking about it for my wagon. Hopping up the engine with too aggressive a cam moves the power range up in rpm. Fun for a while, but sometimes the noise is too much. Yes... maybe I am just getting too old.

All relative to duration....not lift.

Mine is .491 lift/260 duration, lots of bottom end torque

Couple that with 4.38s and a 5-speed.....pretty quick in the 510

 

 

89mm Cant those be found in the L2.8 z motor also ?? maybe a little cheaper than the ka ?

Or the Z24

Will drop the CR a couple of points....but

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I dunno guys, I've spent 590$, which includes:

 

 

 

1 Eaton M62 supercharger, completely rebuilt and ported

 

Custom mounting brackets

 

Custom intercooler and piping, all silicone couplers and T-bolt clamps

 

6 DSM 450cc/min Injectors

 

2 fuel rails (I fucked up one of 'em)

 

1 ITB, dual-plenum intake manifold (not quite finished, need to get it decked and then it'll get bolted up

 

New RB25DE lightweight flywheel

 

New 350Z clutch

 

FS5W71C transmission

 

 

Turbo or supercharging an engine doesn't have to be expensive. Hell, the whole rebuild, including porting the head, boring the block, new pistons, rings, bearings, seals, gaskets, damper, ect. for my L28, was 810$

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I can't see that shopping list of parts being under $600. Unless you made most of it yourself and this isn't available to the average guy's skills. Plus you have EFI which is even more.

 

 

A turbo will shorten the life of any motor, even shorter on an old motor. It's also related to how hard you drive it and how much boost you run. Comparable motors back in the '80 were usually limited to about 6PSI of boost and for good reason. There was little in the way of detonation control and fuel management. If you want your L motor to stay rumming you will need more than a $1,000 rebuild.

 

 

 

 

89mm Cant those be found in the L2.8 z motor also ?? maybe a little cheaper than the ka ?
  

I think the L28 is 87mm.

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I know this is an engine thread but I have not read any one talk about changing the rear end gear and adding a five speed. Unless you are on the freeway alot I think this would make for a peppy ride. I did this in my El Camino, and thinking about it for my wagon. Hopping up the engine with too aggressive a cam moves the power range up in rpm. Fun for a while, but sometimes the noise is too much. Yes... maybe I am just getting too old.
 

 

Yes, a 4.375 in a 510 will make it jump. But it's not unlimited power and top speed and mileage will suffer. It adds no extra load on the motor, is cheap and easily reversed. Adding an overdrive 5 speed will negate most of the drawbacks to this but it does add to the cost. Sealick has some 'gears' in his 510 and with an LZ22 (or was it LZ23?) and SUs, I can testify that it was a neck snapping torque monster.

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 I think the L28 is 87mm.

Ozdat says L28 is 86mm.

 

  Yes, a 4.375 in a 510 will make it jump. But it's not unlimited power and top speed and mileage will suffer. It adds no extra load on the motor, is cheap and easily reversed. Adding an overdrive 5 speed will negate most of the drawbacks to this but it does add to the cost. Sealick has some 'gears' in his 510 and with an LZ22 (or was it LZ23?) and SUs, I can testify that it was a neck snapping torque monster.

Shorter gearing does not always decrease fuel economy, depending on how the engine is built it could be more efficient at higher RPM's.(Less throttle input, same speed)

with an OD 5 speed gearbox, you should be fine with shorter gearing.  

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