suggestions to make a daily driven 620 better

[distributorguy]

There are MANY 5 speed options from the later trucks to the 280Z.  You can get a 5th gear from .91 to .71 gear ratio and almost anywhere in between if I recall.  Yes it helps!!!  You can also get a better 1/2/3 gear ratio so that first isn't a granny gear and spacing is better.   With a little research you can find an online spreadsheet that tells all the gear ratios of this Nissan 5 speed.  

 

The Weber DGV is NOT oversized for the motor.  Its actually about ideal for a 1.4-1.6L engine.  Its progressive, so only a tiny throttle plate opens until you get half-way through the pedal stroke.  Then the 2nd barrel opens, and you get ample fuel/air through all rpms you can drive the truck in.  You never want to reach the full 100% cfm potential of a carb or the mixture will skew.  On my flow bench, most DGVs flow about 220-230 cfm, and I check calibration on my flow bench annually.  The Weber problem is jetting (never seems to be right) and the "power valve" that operates backward forcing the mixture lean on acceleration and rich on decel.  Plus the float levels are never correct.  You need to adjust the float height and float drop to factory specs (available online) plus .001" per 1% of ethanol in your fuel.  The float bowl will need slightly less fuel when running an ethanol blended fuel.  

[Z-train]

Actually,it IS over-sized for a L-20B.It was used on 2.4 motors.And as far as jetting never seems to be "right":

 

[distributorguy]

See how your horsepower peaked with torque?  Your mixture is too rich, and the airflow in your Weber is getting stagnant (choking the engine).  Get that fixed and you'll see you hp peak 1000 rpm higher where it belongs, and it'll grow.  13:1 at peak hp should be your goal. You'll likely need to drill the next size smaller jets to pull it off - part of the jetting issue is that sizes jump in 5s.  

 

If the Weber is too big for the engine, then how did I pull this off???  This is a 240 cid flathead Ford motor, and it ran beautifully.  Its currently powered by 1000 cfm of triple throttle bodies (fuel injected.)  http://advanceddistributors.com/WIllys%20truck.JPG

[Z-train]

See how your horsepower peaked with torque?  1)Your mixture is too rich, and the airflow in your Weber is getting stagnant (choking the engine). 2) Get that fixed and you'll see you hp peak 1000 rpm higher where it belongs, and it'll grow.  3)13:1 at peak hp should be your goal. You'll likely need to drill the next size smaller jets to pull it off - part of the jetting issue is that sizes jump in 5s.  

 

4)If the Weber is too big for the engine, then how did I pull this off???  This is a 240 cid flathead Ford motor, and it ran beautifully.  Its currently powered by 1000 cfm of triple throttle bodies (fuel injected.)  http://advanceddistributors.com/WIllys%20truck.JPG

1)No-it's not.

2)Really? What cam am I running? Where is it's "power band"? HTF can you say this with out knowing how the motor was built? What manifold am I running? What head?

3)No-,it shouldn't

4) Just because you made something work, doesn't mean it's "correct".

[distributorguy]

Lol.  You're one of those guys who isn't going to learn anything from anyone because you know it all, huh?  I submit to your complete and total mastery of the automotive sciences.  I may only have 119 posts here,  but I've been "around the block" a few times.  Please tell me how you mastered the issue with the power valve???  Let's see your dyno sheet with the AFR at 13:1 above 3k rpm???  

 

By the way, there is no "correct."  Only different version of how to make it work.  And the last engines I dyno'd left with 401hp/705tq (4cylinder diesel), 350hp/450tq (GMC 6 cylinder that we never tested above 3000 rpm), 1180hp/980tq (modified Ford 302), 139hp/154tq (Triumph TR6), 101hp/110tq at the wheels (flathead Ford with that DGV setup and sand paddle tires not hooking up - basically a failed event from complete traction loss).  We only dyno'd the Willys because we had the spare time and it was sitting there.  Next up on the dyno, a roller cam MGB with DCOE, A 1380 MG Midget motor with a 4-valve DOHC BMW head and EFI, EFI on the WIllys/Flathead Ford, and hopefully the 2L Bonneville Datsun motor by the end of February (shooting for 250 hp).  

 

 I think I have the experience to make some assumptions about what you're running, and you did a pretty good job with it.  There is ALWAYS room for improvement if you want to make more power.  12:1 is a waste of fuel, unless you're boosted.

[banzai510(hainz)]

Im willing to learn more.

 

weber dgv? I bolt them on and they run

 

101whp from a willyes jeep motor is GOOD!!!!!!!!!!!!!!

[Z-train]

Lol.  You're one of those guys who isn't going to learn anything from anyone because you know it all, huh?  I submit to your complete and total mastery of the automotive sciences.  I may only have 119 posts here,  but I've been "around the block" a few times.  Please tell me how you mastered the issue with the power valve???  Let's see your dyno sheet with the AFR at 13:1 above 3k rpm???  

 

By the way, there is no "correct."  Only different version of how to make it work.  And the last engines I dyno'd left with 401hp/705tq (4cylinder diesel), 350hp/450tq (GMC 6 cylinder that we never tested above 3000 rpm), 1180hp/980tq (modified Ford 302), 139hp/154tq (Triumph TR6), 101hp/110tq at the wheels (flathead Ford with that DGV setup and sand paddle tires not hooking up - basically a failed event from complete traction loss).  We only dyno'd the Willys because we had the spare time and it was sitting there.  Next up on the dyno, a roller cam MGB with DCOE, A 1380 MG Midget motor with a 4-valve DOHC BMW head and EFI, EFI on the WIllys/Flathead Ford, and hopefully the 2L Bonneville Datsun motor by the end of February (shooting for 250 hp).  

 

 I think I have the experience to make some assumptions about what you're running, and you did a pretty good job with it.  There is ALWAYS room for improvement if you want to make more power.  12:1 is a waste of fuel, unless you're boosted.

Resumes?I started wrenching in 1966.You weren't even alive then.You numbers of dyno exercises are moot to this topic.With knowing my build-your input is built on erroneous assumptions.

 

Keep talking.It's entertaining.

[orangie]

.....back to the original topic.  I'd put a good spray in bed liner.  It keeps the bed from echoing so much.

[banzai510(hainz)]

distributorguy

 

hate to go off subject on this thread. I started think how you get 100wheel hp from a flathead ford motor with a DGV. Is a V8 falt head

Datsun.com has L motor with sidedrafts and hard pressed to get 100whp.

I like to know the secret while running a DGV to get at least 85whp w/ L motor.  If you can share this we like to know.

then I wont throw away all those L 16 blocks I had stacked up.

 

 

I had a V6 Capri in Germany a 3 liter Essex motor and ran the ford Weber clone (5200)

claim from factory 138hp  120mph  wgich was done often

[datzenmike]

http://www.datsuns.com/tech/datsundyno.htm

[cr83]

Lol, whenever I start to lose interest in my 620, all I have to do is head to this forum and it sparks my interest again for a long time, thank you ratsun

[Z-train]

.....back to the original topic.  I'd put a good spray in bed liner.  It keeps the bed from echoing so much.

And do the floor of the cab also.

[Kytoaster]

A weber and replacing the non-existent shifter bushings with copper ones (made for a chrystler door hinge), made daily driving massively more enjoyable.

The only other thing I plan on doing (besides recovering my poor bench seat) is to figure out how to get some sort of lsd in my 620.

[distributorguy]

Z-train, If all my "assumptions are erroneous" then please set us ALL straight and tell us the truth...  What is this hot motor you built that's running a DGV?  Let's see photos.  Let's hear build info.  Unless its boosted 12:1 is pig rich, or your O2 sensor is fouled.  

 

By the way, according to your profile and your last post, you started wrenching when you were 6???  Yeah right.  Adjusting your training wheels doesn't count.   :thumbup:

[Z-train]

Z-train, If all my "assumptions are erroneous" then please set us ALL straight and tell us the truth...  What is this hot motor you built that's running a DGV?  Let's see photos.  Let's hear build info.  Unless its boosted 12:1 is pig rich, or your O2 sensor is fouled.  

 

By the way, according to your profile and your last post, you started wrenching when you were 6???  Yeah right.  Adjusting your training wheels doesn't count.   :thumbup:

LZ23

U-67 head-untouched

Rebello cam

L-16 intake-untouched

I don't have a O2 sensor.

And I first picked up a wrench when I WAS 6 helping my Father work on his 66 Pontiac wagon. I never stopped.

CR is at the ragged edge,so it's Rich for a reason.

 

But since before now,you didn't know ANY details on my Build.So tell us all just how in the fuck did you think you were qualified to comment on it?

[distributorguy]

What is your compression ratio and what are your cylinder pressures?

I tune engines for a living.  Some think I am the best distributor rebuilder in the world, tuning more than 1500 a year.  Your engine isn't that unique.  If you read AFR as shown on the dyno sheet, you used an O2 sensor.  

Are you running a DGV?  

 

What makes you think that high compression demands more fuel?  I know a couple Mini engine builders who build 1275 engines at 250 psi cylinder pressures for street use all the time, running SUs tuned at 13:1 AFR.  Yes its extreme, but with those engines it works.  I ran an MG 1.8L engine for 10+ years at 207 psi across the board, AFR ranged from 12.6-12.9 between 3000-5500.  Any richer and I lost 4-9 hp and 10 ft lbs torque.  

[]2eDeYe]

Wow Z-train... you mad about something? 

 

 

If you post something on the internet, someone is going to have an opinion about it whether they are qualified or not. You shouldn't let it get to you :lol: 

 

 

The conversation was about a weber and yes, you can tune one to run on a wide range of motor sizes. That is what various jet sizes and adjustment screws are for. 

 

 

PS there is no weber on your motor in that picture, so if the dyno sheet is for that motor you are just trolling a weber conversation with an EFI turbo. Apples and oranges.

[distributorguy]

That's the thing - its not the engine in the photo.  Who knows where that photo even came from?   He claims to be using a bone stock intake manifold.  My understanding is that the bolt pattern for a Weber is different from the stock boat anchor carb.  Trolls suck.  

 

My whole point is that "off the shelf" jets for DGV style Webers are not precise, and they don't come in small enough increments to tune easily.  You need jet drills to modify them to dial your AFR in to where you want it, plus the power valve setting is ridiculous.  The floats bend when you hit bumps under low fuel circumstances.  There are many issues to deal with to tune one properly.  If you got lucky enough to bolt one on and tune the idle and mixture screws and have it run perfect,  you're the ONLY one!  And chances are, you just aren't aware of what you're missing.  

 

And please don't lie about your experience.  There's no reason for it.  Time doesn't equal intelligence.  And please refrain from using the F-BOMB.  Many times, my 8 year old daughter reads these posts over my shoulder.  She's also an avid gear-head but her favorite cars are custom 60's Lincolns and Caddys.  Not sure where that came from???

[banzai510(hainz)]

Bone stock L16 is only 1.125 intake size

 

most people try to open this up and the top if possible.

 

But loveto see whats possible with a DGV or a 38 DGV. I find this interesting on the power out put as if true I want to know the secret. as a daily driver I prefer a DGV also for the simplicity ease of maint.

[distributorguy]

I suspect that a DGV powered motor could get 150 hp peak given the cfm capabilities, if a non-restrictive air cleaner/intake is used, but that's pushing reality.  A 38/38 would be closer to 200 hp going by simple cfm calculations and the ability to flow up to 325 cfm through that carb, but that's a linear throttle arrangement, not progressive so its low rpm use is less "streetable," unless you like neck snaps and/or spinning tires.  

 

The best way to make more power from a L-series is cylinder head flow bench work.  You could spend weeks figuring out how to maximize airflow, but some basic port work can open up the opportunity for another 30 hp pretty easily, if you can keep the intake/exhaust balance correct.  The downfall is that this can cost $1000-4000 for some good head work.  Guessing usually doesn't produce better overall results from stock, unless you've spent some time learning about airflow (fluid dynamics.)    

[hobospyder]

I have a 38/38 but I think it's a dges on a l16 motor in a 620. When I get the alternator swapped you're welcome to come up for a ride hainz. I think you're in the puget sound iirc. Runs like a champ after the mechanic fiddled with it and got it tuned. Didn't change the jets at all, I can keep up with traffic from sedro to Everett and back again. Low 20s for mpg so not so good for a commuter

 

 

Edit: yeah I'm running a dges and shouldn't have commented. Ignore me

[banzai510(hainz)]

Hobo I had a 38/38 on a Matchported L16 with Schneider cam. Ran pretty good but overjetted as it was for a Landcruiser Intake was black even inside the intake manifold.  But I dont think it will give 90hp to the ground.  Now back to the 32/36. But ist not impressive  Runs fine

 

a stock L16(510) is about 65 hp to the wheel and later swapped L18 was 77 to the wheel what this 1 guy measured. So I bleive that.

 

 

Distributor guy

200 with L20 and a 38/38 is hard to believe ( just the shape of the stock mainifold doing the L shape airforce is going to slow the air up)

 

 

My basic guess is matchport to 1.5 inch, use a  DGV

whats best cam?

[Z-train]

2eDeYe" post="1311094" timestamp="1445959201"]

 

1)Wow Z-train... you mad about something? 

 

 

2)PS there is no weber on your motor in that picture, so if the dyno sheet is for that motor you are just trolling a weber conversation with an EFI turbo. Apples and oranges.

1)Not in the least.Remember the web is a "dead" medium.

2)Yeah,sorta two subjects got merged.He made comments about boost & EFI also.

 

My issue is how can ANYONE make observations withOUT baseline knowledge. Almost everyone here will inquire as to the "build"-he didn't. Just made blanket comments that were in-correct.

[Z-train]

1)That's the thing - its not the engine in the photo.  2)Who knows where that photo even came from?   3)He claims to be using a bone stock intake manifold. 4) My understanding is that the bolt pattern for a Weber is different from the stock boat anchor carb.  5)Trolls suck.  

 

6)And please don't lie about your experience.  There's no reason for it.  7)Time doesn't equal intelligence.  8)And please refrain from using the F-BOMB. 9) Many times, my 8 year old daughter reads these posts over my shoulder.  10)She's also an avid gear-head but her favorite cars are custom 60's Lincolns and Caddys.  Not sure where that came from???

1)No shit-Sherlock-you referenced boost & efi in an earlier post,

2)Bone stock ON THE LZ-23,not my 3.1 stroker. Did you pass English?

3)

Any more stupid stupid statements?

5)Yes,they do-if you stop talking,it'll go a long way.

6)Why are you bothered by someone that has about 20+ years more experience than you? You're twenty years younger than me-you still have time to learn.

7)In your case-true.Not in mine though.

8)**** you.

9)She shouldn't be.

10)That's cool.

 

And here is the LZ motor:

[scooter]

Wow.. lol.. my update for you guys is that the truck is gone.

 

You guys can argue about tuning till the cows come home.

 

I can say my lz pulls harder with afrs below 13, more like 12. That is all.