L20B Dyno

[fiveoneO]

Saw this today, thought someone else might find it interesting.

[sick620]

That’s crazy 130hp stock motor. Okay maybe I will build a l20b for the 510… 

 

I used to have a 710 with a built lz23 and twin delorto carbs. It never saw a dyno but it honestly never seemed all that fast, a bone stock first gem Miata kept up with it .. I now wonder if I just downplayed the importance of dyno tuning an old Datsun. 

Edited November 6, 2022 by sick620

[datzenmike]

L heads breath pretty good but are for 2 liter engine. LZ23 is 15% larger displacement and now it has unrestricted intake air. Still using the 2 liter cam??? Maybe more cam could have made use of both the increased displacement and the much improved induction.

 

 

This is Byron's 2.2 LZ with side drafts and mystery cam. Byron is on the Realm.

[fiveoneO]

I thought those numbers looked a little high for a stock L20B. I have never ran duel webers before and was hoping someone with experience would chime in and say if this is realistic or not.

[RyanC]

I think 100% shows the importance of tuning, also every dyno is different so 130hp is only relevent to this car but I guess ball park.  If it comes in a month later with only 115 then why?

 

I think they also do a video on timing etc.

[datzenmike]

Said Webers and extractors otherwise stock no cam. I don't think so. Stock RWHP is around 95HP. My 710 says 110 but this has to be gross HP and not the newer net HP. My '78 620 said 93. Assuming about a 17% drive line loss 110 X 0.17 = 18.9 or 110 - 18.9 = 91HP at rear wheels. To gain almost 35-40 HP just from a header and side drafts is unlikely.

 

My 2 liter 710 has R1 carburetors and L16 cast iron header. The difference is noticeable on the ass dyno, just.

 

Dynos are great for showing you if you are going in the correct direction with a tune or comparing two engines. Bound to be some difference between two different dynos. If I ever dyno my 710 I'll go see them.

[Skib]

My old L18 with a W58 closed chamber head, 32/36, header, 2-1/4 exhaust, 

electronic ignition and a dogleg made 88 HP and 111 FT/LBs on the dyno.
Iv got a sheet somewhere.... 

[datzenmike]

On a good day...

L16....... 70- 75hp

L18....... 80-85hp... so 88 sounds about right. 

L20B... 90-95hp

[Stoffregen Motorsports]

The stock blueprinted L16s we used to build for SCCA ITC class made 120hp on the engine dyno. Stock everything, but we found the perfect combo of factory parts to optimize everything. A replacement 210 cylinder head with a"TK" surrounded by an oval was the best head and we used a U20 C cam. Other than that, a Weber DGV on an A46 intake and a 2.5" exhaust with a modified long tube header rounded out the package.

 

So 130hp with an L20B? Sure. No problem. Even at the wheels.

[Skib]

16 hours ago, datzenmike said:

On a good day...

L16....... 70- 75hp

L18....... 80-85hp... so 88 sounds about right. 

L20B... 90-95hp

 

 

It was a super nice smooth curve on the dyno sheet so I was very happy.

and those numbers don't seem like much on paper, but in my single cab 620 it should shit and git.

 

 

 

remember kids...... not everything needs 1,000hp to be fun, or fast lol

[DHale_510]

I have had a few carefully built engines tested. I really like to have them broken in and tested on a dyno when available. The Oregon experts [MOFO Meadows discussions for the old timers] never agree with the results, but never really show alternatives.

My Potter built L20 with Mikuni 44s and a carefully stock U20 cam ran 150 hp and 150torque over 1500rpm and has over 200k miles. Its the car we taught with at the Thunderhill schools for about 10 years. It was named the Datserati by a friend many years ago.

One of my demon tweaks was to make Monel valve seats. It has never needed a valve adjustment. Monel is nickel/copper alloy.

My last Rebello built L20b with microsquirt fuel injection and a stock cast manifold and Miata sourced AC tested at 164hp and 175tq crankshaft, from 3200 to 6000 rpm. Both motors have cast pistons and 5500 rpm limits. Both were "too expensive" builds, maybe twice the cost of the day.

I have built a couple hundred motors, largely beetle ones, and I respect those who can out do me. Maybe you get what you pay for.

I had Rebello build a big Z car motor for a hillclimb car to chase Kipperman with his LS powered 240Z. We made a 3200 displacement and all the tricks I shouldn't have bought and got 350hp and 270tq at 6700rpm. It ran over 300hp from 5500 to 7800rpm. The car has never been completed... 

Then there is the motorhome 510ci motor with 500torque and 480hp. It did about 120 on the dyno. It uses factory TBI. It tows well.....

Dennis

[paradime]

Impressive. Sounds like you got what you paid for Dennis.

 

The L20B I swopped into my autocross 510 was the first race engine I built on my own. Fairly stock bottom end with balanced crank and 10:1 compression (most from pistons). Camford Racing in SoCal did the head with gorgeous port and polish, 46mm Intake and 38mm Exhaust valves, machined alloy seats, bronze guides, stage 2 Nissan Performance race cam (forget the lift but it idled like an epileptic), and stiffer springs. With 44mm Webers and tube header the most I got out of it was 142hp at the wheels. I left the jetting on the rich side because at 20 yrs old I couldn't afford to push things and blow it up. All the same, I did some serious damage to the egos of muscle car guys with that 510.  What a blast.

Edited November 7, 2022 by paradime

[Stoffregen Motorsports]

I freaking love a lopey idle.