Hot LZ23

[Bastard_510]

14 hours ago, scooter said:

Looks very nice! What did you end up with for deck height? I assume you just ended up sendin it with the side clearance?

227.358mm 8.9511". no i had a crank sent and its .01" now.

[Bastard_510]

 

[Stoffregen Motorsports]

227mm deck height?

 

I think he was asking where the pistons are (piston deck height). How far under deck surface?

[Bastard_510]

58 minutes ago, Stoffregen Motorsports said:

227mm deck height?

 

I think he was asking where the pistons are (piston deck height). How far under deck surface?

Yes 

 

after video i pulled out a depth mic and it’s 1.5 thou in the hole (deck clearance).

Edited September 1, 2019 by Bastard_510

[Stoffregen Motorsports]

It is safe to run them .010" to .015" above deck.

[datzenmike]

Jason gray mentions 1/3 mm as the limit above the deck. With a 1.2mm crushed gasket this leaves just under a mm for any high RPM rod stretch.

[scooter]

Looks good!

[Bastard_510]

I have a .04” (1mm) gasket before crush. I tend to like round numbers and the engine is dead at 12:1 shaving 15thou off the deck would be 12.7:1

i don’t feel comfortable taking that much off the deck with a repair and i wouldn’t gain anything from it. If anything i could take out the dish and have 13:1. 

 

1/3MM=.013 i think...now I’m not completely sure on this one...that’s between .010-.015

 

 

thanks scooter

[Stoffregen Motorsports]

Under deck though, not sticking out of the deck surface. Right?

[Bastard_510]

Under by 0.0015

[scooter]

is this thing going to run on E85?

[Bastard_510]

35 minutes ago, scooter said:

is this thing going to run on E85?

No 91

[scooter]

40 minutes ago, Bastard_510 said:

No 91

if this works out for you send some of that 91 my way!

[Bastard_510]

1 hour ago, scooter said:

if this works out for you send some of that 91 my way!

That’s what I’m saying. You all get your panties in a bunch when someone says 12:1. You can run any STATIC compression you want but if you’re going to run pump gas your EFFECTIVE compression has to be 8 or lower. MATCH YOUR STATIC COMPRESSION TO YOUR CAM DURATION. If you take a stock L20 and put a 280duration cam you can advance your ignition stupid high because it’s not making the compression to detonate. Same with a lz22 stock build. I know of two people that blew theirs up from having the wrong cam. If you use a stock Cam on anything higher than 9:1 you gain cylinder pressure but you have to back the timing off. 

[scooter]

make it run allready 😄 

[datzenmike]

True at lower RPMs with longer duration.

 

At higher RPMs the later closing intake allows more time for more of the high speed air to get in from inertia before the door closes. You can easily get more air in than a stock cam and it's possible to go higher than 100% volumetric efficiency or above 12 to 1. More air = more compression = more power. Or why have a longer duration cam?  It may be 8 at idle but it goes up with RPMs.

[Bastard_510]

20 hours ago, datzenmike said:

True at lower RPMs with longer duration.

 

no. it tays the same at all RPM. please show me were i can change my intake closing event while the engine is running. at extreme low rpm the pulse from the piston traveling back up while the intake valve is open can be seen or heard on a cammed engine when the throttle is snapped open. 

 

20 hours ago, datzenmike said:

 

At higher RPMs the later closing intake allows more time for more of the high speed air to get in from inertia before the door closes. 

yes/no. this is true but this pulse is not going to give you anything over your static and will not effect the effective compression. the key to effective compression is the degrees ABDC that the intake valve is closed. if you have a 8:1 SCR with a 280 dur cam youll have a 5.6:1 effective ratio ECR. the late timing may help start flow but it will bleed some of the air/fuel mixture back into the intake. 5.6:1 GARBAGE. since everyone wants a big cam you have to match it with compression so 12:1SCR with a 280 cam closing at 69 degrees ABDC gives a effective compression ration of 7.7:1 (perfect). if you look at a good cam grinder's catalog you will see they want to match compression with the cam they are selling. so really you are building an engine around your cam. Dont believe me? i have articles you can read. 

 

20 hours ago, datzenmike said:

 You can easily get more air in than a stock cam and it's possible to go higher than 100% volumetric efficiency or above 12 to 1. More air = more compression = more power. Or why have a longer duration cam?  It may be 8 at idle but it goes up with RPMs.

you will not get 100 VE with just a cam swap. its a lot of money and research to get 100 VE out of a NA engine. the only time you have 100% VE is when the engine is turning over or if its large enough the engine RPM is low and being stalled on a dyno. when porting a head you are chasing VE with the goal of having a better VE at a higher RPM (moving your torque curve) because the engine at 5K only has .005" to fill the cylinder. that makes it hard to move air in.  with a good VE  you will have to worry about bleeding off some of the pressure in the cylinder to keep cylinder pressure below the risk of detonation. thats where the late intake timing comes into play. too late IVC will bleed off too much pressure and make your engine a dog. Too early IVC and you will have to retard the cam or retard the ignition timing to keep cylinder pressure under control. this is why some people with a lz22 with a stock cam have 5* BTDC ignition timing.

 

20 hours ago, datzenmike said:

It may be 8 at idle but it goes up with RPMs.

well i just explained 8:1 ECR. next time you have your spark plugs out take a compression tester with the schrader valve removed. put all put one spark plug in and start the engine. you'll see that at idle the compression is low 80-100psi. thats because that cylinder is only part full of air since the throttle is closed. open the throttle and the needle on the gauge will climb and stop. that will be the effective compression at peak VE. if you had a dyno and were able to stall the engine at idle with  WOT you would see the same peak  on the compression gauge or close to it,but that would kill the engine. the slower the RPM the more time air has to rush in. this is called cylinder pressure not effective compression.

 

 

On 9/3/2019 at 10:43 PM, scooter said:

make it run allready 😄 

Edited September 5, 2019 by Bastard_510

[datzenmike]

I'm trying to understand why your theory on this is so different to mine. I'm not convinced so lets agree to disagree.

[Stoffregen Motorsports]

On 9/3/2019 at 7:17 PM, scooter said:

if this works out for you send some of that 91 my way!

I have run a few L street motors with very high compression and on street gas. It is possible.

[Bastard_510]

a formal education in automotive and a strong passion for engineering(soon to be formal). but i will agree to disagree. it took me a while to understand it and its better to see it on a dissected engine then as text on a screen. 

 

im working on the seats right now on. after that its final cleaning, inspection, test fit, and assembly. the plan is to get it put in the first week of october. i still have to weld my 8.8 up and have some 4 link brackets and axels made to fit. im thinking of keeping the 4x114 pattern so it looks stock.

[scooter]

Solid rear end in a 510? If you want ratsun style look at 90-92 ranger 8.8”s they are 56 inches wide. ( i think stock 510 is 54”? )The 28 spline axles are strong enough for datsun use. If you take a hair off the od of the axle flange s13 rear disc will slide on. Your choice for 4 or 5 bolt 

[Bastard_510]

8 minutes ago, scooter said:

Solid rear end in a 510? If you want ratsun style look at 90-92 ranger 8.8”s they are 56 inches wide. ( i think stock 510 is 54”? )The 28 spline axles are strong enough for datsun use. If you take a hair off the od of the axle flange s13 rear disc will slide on. Your choice for 4 or 5 bolt 

Watch the video you’ll see what it’s going into. I’m not going by an existing amount. I’ll chop as much as i need to fit 205’s and the same rims hopefully and make it look nice. Looking to keep a 3.54:1 ratio with an lsd. I’ve had a 8.8 in my back yard for over a year now. It’s an open 3.27 open with disks. i was snooping around your thread, how did your brakes feel with the s13 calipers?

[scooter]

I am actually using 200sx front calipers on the s13 discs on the rear (no e brake) the feel and stopping power is good for what it is (loaded calipers with bracket was like 15 dollars)

 

But the pads are kinda poo and go away when really hot.

i now have a set of 280zx casings that in going to shorten for the front as im using 84 200sx front struts right now. My only reason for changing is to get better brake pad material as theres no good pads for 4cyl s12 brakes. 

 

Im happy with what i have on it in general right now but it does fade if you do a few 200-20 hard brakes. Friends of mine have focus rs’s 350z’s and evos and shit and i definitly cant outbrake them but still good enought to not crash lol. 

 

As for gear ratio, on the street the 3.73:1 was good. Im using 205/60/13 tires as well.

although with the s13 overdrive its a little under the curve at 100kph, its alot happier in 5th at 120-130 kph. I used to have the hardbody overdrive in it which made the car happy to cruise at 100-110 in 5th.

going to 4.10’s should put my 5th gear roughly back to where it was before.

 

your gears are gonna be pretty long with 3.54 gears. If you have a real light clutch/flywheel setup it may be a lil hard to get going.

[Bastard_510]

On 9/8/2019 at 7:19 PM, scooter said:

 

 

your gears are gonna be pretty long with 3.54 gears. If you have a real light clutch/flywheel setup it may be a lil hard to get going.

 E brake is a must so I’ll find a way to use the stock 8.8 disks. . Yup that’s kinda the point.

1st 38MPH

2nd 66MPH

3rd 96MPH

4th 126MPH

5th 167MPH lol

 

70mph at 2,700rpm in 5th

It’s for freeway/highway/ road trips it’s getting a 15~ pound flywheel and a clutch i haven’t looked into yet. 

Edited September 11, 2019 by Bastard_510

[scooter]

fair enough. Also if you feel its too much and its too big of a jump between 4th and 5th you can put the hardbody 5th gear in the tranny to get a closer ratio there.  

 

From what i remember of the 8.8 discs you need to run 15 inch or bigger wheels. The disc is also pretty big so to even it out your going to have to run a 4 port brake bias adjuster or big ass front calipers and rotors as well (300zx) or both. Prob gonna have to get a little bigger master cylinder as well.

 

back to engine shinatigans!