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Most HP ever from a n/a L4 Nissan L20b


Mrfixit

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Troy just built a L20b (2050cc per the rules for the class) 10.1 compression on pump gas with 44mm Mikunis and it made almost 145hp at the wheels I am not sure if Troy or the owner kept the dyno sheet but I was there and watched the dyno myself

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Keith Law's turbo L20B is 249 hp Merlin.

 

 

Hi guys

 

What is the most horsepower ( engine dynoed)you have heard of being made by a naturally aspirated L20b Nissan L4.

 

 

The thing is ...A motor built to this is undriveable on the street. You would need much taller gears to keep it revved up where it makes enough power to actually move the car. Keith Law as mentioned above runs 4.625 rear differential and aviation fuel NOT CHEAP. The car is great out on the highway and with the gears drivable in town but not recommended. Other drive line parts have been replaced or modified to withstand the power. Even NA some of this must be taken into account.

 

Try a larger motor like a KA. Makes at least as much as a full bore L20B would, and it's reliable, EFI, loads of torque.

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GO ON YOU TUBE TYPE IN DATSUN L18 DYNO DAY, NA L18 IN A BRE 510 MADE LIKE 180HP TO THE WHEELS, ALL ABOVE 6000RPM. THROW A CAM IN IT, THROW ON SOME DUAL CARBS, CALL IT GOOD!!!!!

 

once you get l in this horse power range it is not fun to drive in stop and go traffic. on the free way it is fun though !

 

braden's hainz quote is right!

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So in a full race engine 250hp is not possible

full race??? like what are you talkin about...

 

the full race L20b in Troys old 710 race car made almost 200 at the wheels but thats 12.1 compression aftermarket rods and pistons and 50mm carbs and is NOT streetable... are you building a race car or something to drive on the streets on the weekends

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does anyone run nitrous on l motors for quick hp? just wondering how it would respond to nitrous good or bad. i have a nos setup here that ive been thinking about running with 50 shot jets, but im curious to see if anyone here has ran it....

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  • 11 months later...

The most powerful L-20B I knew of was one built by Frank Honsowetz in the early 90's. It put out 215 HP with the power band starting at 6000. It has the later FIA cylinder head and the twin 50mm Solexes. It's still around, but hasn't run in about 15 years. No nitrous, nitro, alcohol, or other BS, just race gas like everybody else was using at the time.

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I saw on a facebook page where a guy was building a l20b with full billet segregated dry sump sump , crank trigged ,DLC coated camshaft and lifters race engine and was claiming at least 250hp . I haven't heard of anyone making that

at this point its not a datsun engine anymore, just some fancy one off parts with datsun printed on the valve cover.tongue.gif and yah, not streetable. my dads 2276cc air cooled bug is pushing 200 hp n/a with dual 48 ida downdrafts and a fat ass cam and 2000 dollar heads. overall engine costing like 9k and its definately not fun to drive on the streets, unless that is if you are mashing your foot into the floor 24/7, and at 5 mpg, thats not a good ideaa haha.

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in the april 2011 issue of super street magazine there was a 510 with an na l20b that made 230hp it measured out to 2288cc with kameari forged 89mm pistons z20 rods and a z22 crank with an fia head and a 300 degree isky cam and 50mm solexs

 

 

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Guest kamakazi620

in the april 2011 issue of super street magazine there was a 510 with an na l20b that made 230hp it measured out to 2288cc with kameari forged 89mm pistons z20 rods and a z22 crank with an fia head and a 300 degree isky cam and 50mm solexs

After all that^^^^^^it's no longer a L20b its a 2.3 stroker race motor not streetable BAD MPGs Hop up a KA and it will have WAY more torque and better mpgs you need torque NOT HP

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  • 5 years later...

Back in 1987 I worked at HamFab and prior to that I had been building in my garage for about a year an L20B block I had picked up at a garage sale, and the large port SSS head at FarPerformance Swap Meet in Mountain View, across from Garretson Enterprises. I then spent about $1,800.00 at CompTECH Machining in Sunnyvale, CA as they machined the block, porting, polishing heads, Shot-peen rods, de-burr block, balanced (everything down to the water pump pully), lightened the L20B flywheel to 11lbs which was also machined and balanced, exotic racing pistons and Cam from NISSAN. I ended up with about 10:1 compression, and measured 240 psi per cylinder one cylinder was 237 psi.

In total I had spent about 10K on the motor itself over about  20 months.

This build included used 44 Mikuni Side Draft long manifold. The Mikunis were modified with larger jets etc.  The heads I had CC'd myself at the shop (HamFab).  I learned a lot about race cars at HamFab as that is all we built "race cars" (mostly Porsche and Audi) and so many exotic engine and suspension modifications that would make your head spin.  Thanks John Hammill and Bob Fernandez you guys are the best!!! Great times.

I had mated the 280Z 5speed to the L-20B fairly easily though the clutch fork was different and so was the slave cylinder. I also reversed the transmission crossmember to fit properly and redilled holes and the shift hole was further back by about 5 inches. The driveshaft was custom made in Hayward but I don't remember who it was.

I found some info on the transmission swap as someone else doing this in the 5nDime magazine.  I used to lick stamps for Rex Janett at this house in Mountain View for the 5nDime magazine. Rex had a few sweeeeet 510's and one plain mint condition stocker. Ok back to the 71 510.

I took the 610 struts cut them to 240z height and welded on threaded sleeves to accommodate 24o lb adjustable coil overs.  Tilton Camber-Castor plate was installed and the castor was set about 5 degrees aft from stock (most people don't understand why this matters) but its very helpful for high speed stabilization keeping the car tracking straight. Cut the springs in the rear and slotted the rear cross member (slotting was done at FarPerformance, Mountain View only 1/2 mile from my house at the time) I machined 1" bump steer spacers out aluminum and hardened bolts 1" longer. All bushings were Teflon by Tilton. Mated with 240z brake calipers and rotors with a special offset bracket that was machined at HamFab for the 610/ 240z mating.  Many more mods to the motor that included crank fire MSD ignition and Jacobs Coil,  Large fuel pump, Large Racing Nissan Oil Pump. ( I was about to install a sump system but never did). This 510 had put out about 218+ hp with 92octane and some octane boost infused in the gas tank. Its all in the detail.  The electronic tack was noted to have witnessed 9k rpm and was still accelerating hard... I backed off but the motor was a smooth as glass. I did not want to go much past the 9k rpm as shifting into 3rd at over 70mph gave an unexpected chirp. The cynthrithical clutch with counter weights was a big help in connecting the engine to the trans.

Well I know its possible to squeak out 250hp if it is done right and spend a bit more money on a better intake system than the 44.

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That's a great story. I recognize most of the places and people you mention as I was involved with SCCA road racing at the same time. I was just out of high school, but picked up a job working for Dave Rebello at his shop in Concord. Traveled the country with him and a couple racers (Sal Versaggi and John Goddard) on the NASPORT circuit.

 

I built a lot of the GT4 and GT3 engines at the time and the L16 GT4 engines were producing 230 hp, at the flywheel, with dual 50 Mikunis. I didn't do any of the port work or cam design, that was Mike Yoes and Dave Rebello, but all of the rotating assembly mods and the entire assembly was up to me. It was a fun job.

 

I think something has been lost over the years, something that makes a true high rpm "all motor" racing engine so exhilarating.

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