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lampy's datsun 1600
http://www.ozdat.com.au/forum/viewtopic.php?t=20290		 Page 12 of 14
Author:  lampy [ Thu Sep 04, 2014 5:34 pm ]
Post subject:  Re: lampy's datsun 1600
Well the tuning day was a success. No major issues
Got about 40-50 laps in during the day so gave the car a fair workout.
Managed a 1:08.5 lap time which is not too bad for a new car. My old 1600 used to do a 1:13
Need to get down to 1:06 to be competitive with the top u2l cars.

Tyres were fairly old (around 3 yrs) so that was probably letting the car down a lot. New tyres for next event

The car was very taily and just wanted to come around on me all day. Even on turn in which is unusual for a 1600.
This has to do with the roll center adjustment i made on the rear.
I replaced the swaybar after the first run 1.2mm to 1.6 mm wall thickness and that didnt seem to make much difference.
Backing off the bump and rebound on the rear shocks helped a lot

I have ordered new lower rate rear springs. 1100 down to 900 lbs and had them made a bit lower.
Hopefully this will help with the oversteer.

Camber needs to be adjusted. Rear camber needs to go from -1 to -3
Front camber needs to go from -3 to - 4

Brakes are also fairly horrendous. They dont have any feel or bite. I think it might be the pad compounds.
I am running QFM comp 9 on the front and comp 2 on the rear. I have bought as of yesterday Ferodo ds3000 for all corners. Hopefully they will be better

Had a little leak of oil from the rear seal on the gearbox. Need to replace the seal again.

Diff temperature got a little hot after about 10-12 laps.
Saw 150 degrees for a little while. Need to sort out a cooler soon.
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Author:  Azzdat16 [ Thu Sep 04, 2014 7:00 pm ]
Post subject:  Re: lampy's datsun 1600
Awesome mate!
Datto's on the track always look cool!
Author:  bobs your uncle [ Thu Sep 04, 2014 7:44 pm ]
Post subject:  Re: lampy's datsun 1600
Just a thought, the last rear g/box seal I did turned out to be the plug in the tailshaft yoke having a slight leak and slinging oil everywhere. Seeing the words rear g/box seal AGAIN prompted this reply . hope it helps Bob.
Author:  Coz22a [ Thu Sep 04, 2014 8:19 pm ]
Post subject:  Re: lampy's datsun 1600
That's awesome
Congrats on a fantastic build, sounds like you can now enjoy all the hard work.
:thumbsup:
Mick
Author:  lampy [ Thu Sep 04, 2014 8:24 pm ]
Post subject:  Re: lampy's datsun 1600
Quote:
Just a thought, the last rear g/box seal I did turned out to be the plug in the tailshaft yoke having a slight leak and slinging oil everywhere. Seeing the words rear g/box seal AGAIN prompted this reply . hope it helps Bob.
Interesting!
Not sure what the problem is yet. Havent had the time to pull it out.
Oil was definately slinging off the tailshaft yoke, but i thought it was a seal gone.
This was the first run on a brand new seal and a tailshaft i have never run before

Where is the plug on the tailshaft yoke? Down the middle?
Author:  bobs your uncle [ Thu Sep 04, 2014 9:20 pm ]
Post subject:  Re: lampy's datsun 1600
Drop the yoke off the universal joint, using a wire wheel clean off all the old grease, oil and paint back to bare metal inside the "U" Knock the plug out using a old g/box main shaft or suitable diameter solid rod. Clean up the plug on a wire wheel and area where it's locates on the yoke. Mix up plenty of Arraldyte and glue around the perimeter of both the plug and fitment area, knock in using suitable size socket. Pin punch 4/5 times around the outer lip of yoke hole to retain plug. When glue is dry add additional glue right around plug and yoke. Bob.
Author:  Anth510 [ Fri Sep 05, 2014 11:24 am ]
Post subject:  Re: lampy's datsun 1600
looks great out there, congrats :)
Author:  SR20Datsun [ Fri Sep 05, 2014 7:26 pm ]
Post subject:  Re: lampy's datsun 1600
Congratulations Hayden. I bet you are one very happy Datsun driver. Good to see a few photos of it out on the track, and good to hear the only issue was handling and a leaking gearbox.

Based on a few photos previously in your build, the back end looked high-ish and your suggestion about lowering it a bit will raise the roll centre which will increase the roll stiffness on the back end. You mentioned adding negative camber to the rear and depending on what kind of rear end you are running, this typically lowers the R.C. down. Perhaps just lowering the rear end will add enough camber due to the natural camber change of the semi-trailing arm suspension, so no point in over doing it?

Interesting about the brakes. Maybe a stupid question, but were they getting up to temperature? You do have pretty large rotors! I'll be interested to hear feedback on how the Ferodo compound compares. I'm only running QFM A1RM's and they are fantastic for what I need and right smack bang on the temperature range.

Diff temperature is interesting. This is something that I have been chasing on my car for some time. I'm currently running an R180 3.9 and not a 5.1(?) that you are running.
I assume you have already done a fair bit of bedding in drives (figure eights etc.), so that would rule out and you did shot pean and micropolish from memory. What viscosity oil are you running? I'm currently running Motul Gear Competition 75W-140 (blue stuff) and it foams something shocking, which certainly doesn't help with heat transfer. I'm thinking of dropping it down to a 80W-90 with a small bit of Molybdenum Disulphide which I think will help the temperature issues. I'm also contemplating running an R200 (for a variety of reasons), but that's another story...

Good luck mate, the majority of build is done, now the fun starts with the tweaking! Eager to hear back how you go.
Author:  lampy [ Tue Sep 09, 2014 12:41 pm ]
Post subject:  Re: lampy's datsun 1600
Quote:
Based on a few photos previously in your build, the back end looked high-ish and your suggestion about lowering it a bit will raise the roll centre which will increase the roll stiffness on the back end. You mentioned adding negative camber to the rear and depending on what kind of rear end you are running, this typically lowers the R.C. down. Perhaps just lowering the rear end will add enough camber due to the natural camber change of the semi-trailing arm suspension, so no point in over doing it?
From my research i think lowering the rear will result in the roll center being lower and thus less roll stiffness on the rear. Feel free to correct me?
The back of the car is definately too high, especially in cornering. Maybe this could be due to jacking forces if the roll center is too high on the rear??
Either way the rear is too stiff, the car gets fairly unstable over a particular bump in the track and makes the rear end want to come around.
Hopefully once i lower the rear with the new springs the negative camber will come down to where i want it and the roll stiffness in the rear will reduce.

To get my negative camber on the rear with the raising of the inner pivot (for roll center adjustment) the trailing arms has to be modified at the axle/bearing housing, so i dont really have a good adjustment of camber, except adjusting the inner piviot up or down, which in turn adjusts the roll center.
The old datsun semi trailing arm suspension gets fairly complicated when tuning :|

The brakes were getting up to temperature. The infra red gun was showing 350 degrees on the front and 300 on the rear. Interestingly the comp 9 and comp 2 pads should work at similar temps to the A1RM.
I know the ferodos are a proven thing so will go with them. There maybe still air in the system somewhere. I am going to have to do some faultfinding.

The diff oil i am running is ULX-110 85w-140. It was recommended by the guy who put together the diff.
I did do a little running in, maybe not enough. It is fairly hard to find a bit of bitumen that i can do figure 8s in with a super loud racecar.
I think a cooler is definately needed. r180's and even r200's seem very prone to overheating with clutchpack centers.
It is a simple task for me. The wiring already has the diff pump installed. Just need to find a small cooler, a place to mount it and some hose

Hopefully going to get it back on the track in the next few weeks. Neet to get a new set of r888 tyres
Author:  SR20Datsun [ Tue Sep 09, 2014 2:15 pm ]
Post subject:  Re: lampy's datsun 1600
My understanding (correct me if I am wrong though!) is lowering the rear end raises the roll centre in relation to the differential. By raising the arms you are effectively decreasing the roll centre couple to the COG. I know what you mean with the roll centre being lower toward the ground, but (and I need to make sure this is correct) if you lower the car by 1", the roll centre doesn't lower 1". I think (again correct me if I am wrong) it is closer to staying where it was while the car is lowered around it.

Yeah, bloody semi-trailing arm suspension!
Author:  Mr Dazda 13B [ Fri Nov 07, 2014 1:25 am ]
Post subject:  Re: lampy's datsun 1600
Lampy, Great to see the car in action tonight, Sounded wonderful. Great Build.

BTW where do you get the ULX oil from?

Cheers


John
Author:  lampy [ Fri Nov 07, 2014 3:23 pm ]
Post subject:  Re: lampy's datsun 1600
Good to meet you as well John.
Hopefully i get to see the Dazda used in anger sometime :)

the ULX oils are hard to get in WA. I got mine from Sam at neat gearboxes in SA but am running out fast. Need to find someone in WA that supplies it.

Just uploaded a video of our run 4 last night. Took it fairly easy after it started raining as it was like ice out there.
http://youtu.be/enILB7CSJx4

Turn the volume up 8)

Good to meet Jack as well. Hopefully he returns in a grunter datsun
Author:  Dave [ Fri Nov 07, 2014 6:33 pm ]
Post subject:  Re: lampy's datsun 1600
Sounded awesome. Seemed to go all right too :shock:
Author:  Anth510 [ Fri Nov 07, 2014 6:35 pm ]
Post subject:  Re: lampy's datsun 1600
GRUNTER!

Gotta admit I'm not used to seeing wipers go that fast in a Datsun :lol:
Author:  SR20Datsun [ Fri Nov 07, 2014 6:48 pm ]
Post subject:  Re: lampy's datsun 1600
Thats sound... made me want to shift early...
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