DIY Electric Car Forums banner
361 - 376 of 376 Posts

·
Administrator
Joined
·
6,443 Posts
Discussion Starter · #361 ·
Do you think TIG welding would also be a bad idea, due to the potential of ripples? Or was that specific to brazing? I really like the idea.
The problem was the heat from the brazing - MIG or TIG should be better
There is also the rivet and glue approach - which I found tempting but chickened out as I was not sure about getting it through our certification process
 

·
Administrator
Joined
·
6,443 Posts
Discussion Starter · #362 ·
Im wondering if anyone here has sucessfully welded to car sheet metal with a arc welder? (cheaper than other types of welders) It seems possible if you turn the welder right down and tac weld back and forth with stops to cool?
Yes I have done a fair amount of that in the past - it requires much more careful preparation than gas welding but it is doable
 

·
Registered
Joined
·
224 Posts
I know you've increased your tire diameter to decrease motor RPMs, is it worth changing diff gearing? Did the increase in tire diameter noticably decrease your low speed power at all? Seems like you have plenty of it?
 

·
Administrator
Joined
·
6,443 Posts
Discussion Starter · #364 ·
I know you've increased your tire diameter to decrease motor RPMs, is it worth changing diff gearing? Did the increase in tire diameter noticably decrease your low speed power at all? Seems like you have plenty of it?
Not really
I went from my 195/60/15 to 225/45/17 Nittos to get more grip - THEN I went to 235/45/17 Nexxens to drop the revs a wee bit but mostly so that I could use the Nittos on the front when on the track

195/60/15 --- 518/km - initial -- RPM at 96 mph (153 kph) - 5436 rpm
225/45/17 ---- 502/km - 3% larger RPM at 96 mph (153 kph) - 5248 rpm
235/45/17 ----- 495/km - 4.6% larger RPM at 96 mph (153 kph) - 5175 rpm

I'm having difficulty getting the Nexxens to grip - the slightly smaller Nittos appear to have more grip - so that is the limit - not the available torque

A taller diff might help - If I see one I will grab it - currently a 4.1:1 Subaru limited slip diff
 

·
Administrator
Joined
·
6,443 Posts
Discussion Starter · #365 ·
Not really
I went from my 195/60/15 to 225/45/17 Nittos to get more grip - THEN I went to 235/45/17 Nexxens to drop the revs a wee bit but mostly so that I could use the Nittos on the front when on the track

195/60/15 --- 518/km - initial -- RPM at 96 mph (153 kph) - 5436 rpm
225/45/17 ---- 502/km - 3% larger RPM at 96 mph (153 kph) - 5248 rpm
235/45/17 ----- 495/km - 4.6% larger RPM at 96 mph (153 kph) - 5175 rpm

I'm having difficulty getting the Nexxens to grip - the slightly smaller Nittos appear to have more grip - so that is the limit - not the available torque

A taller diff might help - If I see one I will grab it - currently a 4.1:1 Subaru limited slip diff
On the 1/4 mile I got to 104 mph (no traction at the start)
195/60/15 --- 518/km - initial -- RPM at 104 mph (168 kph) - 5946 rpm
225/45/17 ---- 502/km - 3% larger RPM at 104 mph (168 kph) - 5762 rpm
235/45/17 ----- 495/km - 4.6% larger RPM at 104 mph (168 kph) - 5682 rpm

No chance of getting there with the 15 inch wheels! - no grip
I intend to try the Nittos at the next meeting

The chief forklift motor Guru (Major) has said that my motor "should" be OK at 6500 rpm !!!
At 6000 rpm with the Nittos I would be doing 175 kps - 109 mph

At 6500 rpm - 189.6 kph - 118.5 mph
 

·
Administrator
Joined
·
6,443 Posts
Discussion Starter · #366 · (Edited)
Went Drag racing on Sunday
Great day out
I joined the local club so they put me in their shoot out - randomly selected lanes and opponents
First run against a turbocharged 5 liter Mustang - I won
Second run against an M3 BMW - I won
Third run against a supercharged and nitro Falcon - I won
Fourth Run - this guy had a bloody parachute bolted to the back of his EVO - I lost!

I only have the times for the last run
1/8th mile - 7.987 - 95.1 mph
1/4 mile - 12.218 - 109.5 mph

The EVO nearly broke into the 8's - 9.01 and 157 mph

109.5 mph is 6045 rpm - I think I need slightly taller tyres
 

·
Administrator
Joined
·
6,443 Posts
Discussion Starter · #368 ·
Did you note the EVO's time/speed in the eighth?
It did 5.967 and 125.4 in the 1/8th

It was going a lot faster than me at the end but when he opened the parachute I was leaning hard on the brakes to stay behind him - then he stopped to remove it and I tootled past him and around the rest of the track
This drag race was set up as part of the Teretonga circuit so after the drag bit you are meant to drive sedately around the rest of the circuit - which of course is what I did!
 

·
Administrator
Joined
·
6,443 Posts
Discussion Starter · #370 ·
A couple of autocrosses - video on my Youtube page

Last Sunday we had a triple event - 1/4 mile drags - grass autokhana and tarmac autocross

Tried something new for the drags - 40 kg of sand in the boot

Made a HUGE difference - ended up with an 11.75 !!! - the next fastest guy was 12.54

The grass event was a wee bit bumpy but fun

Then in the Autocross the organizer asked if I would take a passenger - I said yes and took one of the lady firefighters
(took the sand out)
Made a surprising difference - the car felt much better with a passenger - I ended up 4th - I'm normally more like 14th

With that behind me I went to the Good Friday Drags - used the sand again but could not quite get below the 12 seconds - the Autocross club uses a timer that starts when the car breaks the beam - which means that my 0.3 seconds reaction time doe not count

Still had a great time
First run was against a supercharged V8 T bucket - his reaction time was better than mine - we were almost level at the end but he was just in front
Then a nice newish white Falcon - beat him
Then another supercharged V8 T bucket - beat him

My last run was against the BMW M3 that I beat last time - he had got a "chip" and some drag tyres
A great race! - he beat me by about the length of his bonnet!

Last event for this season - My device has been on the road for 9 years so its time for some paint and a bit of a rework

I'm thinking about moving some of the batteries into the boot and trying to lose a bit of weight (the car as well)

I'm 55/45 rear/front at the moment - should I aim for 60/40 ???

Any thoughts?
 

·
Registered
Joined
·
1,765 Posts
[\quote]
Tried something new for the drags - 40 kg of sand in the boot

Made a HUGE difference - ended up with an 11.75

I'm thinking about moving some of the batteries into the boot and trying to lose a bit of weight (the car as well)

I'm 55/45 rear/front at the moment - should I aim for 60/40 ???

Any thoughts?
[/QUOTE]
Sandbag and passenger suggests you're traction limited. Ever go rock hard on the tires and did it get worse or go softer and it got better? In my V8 pinto we ended up with 15 psi in the rear M50-15 but should have used bead locks.

Sandbag also trends towards 50/50 but moving batteries means re doing the cables which would be a can of worms. Could add a couple of ohms and reduce motor power significantly. What happens with 2 sand bags or even 3?
 

·
Registered
Joined
·
3,090 Posts
A couple of autocrosses - video on my Youtube page

Last Sunday we had a triple event - 1/4 mile drags - grass autokhana and tarmac autocross

Tried something new for the drags - 40 kg of sand in the boot

Made a HUGE difference - ended up with an 11.75 !!! - the next fastest guy was 12.54

The grass event was a wee bit bumpy but fun

Then in the Autocross the organizer asked if I would take a passenger - I said yes and took one of the lady firefighters
(took the sand out)
Made a surprising difference - the car felt much better with a passenger - I ended up 4th - I'm normally more like 14th

With that behind me I went to the Good Friday Drags - used the sand again but could not quite get below the 12 seconds - the Autocross club uses a timer that starts when the car breaks the beam - which means that my 0.3 seconds reaction time doe not count

Still had a great time
First run was against a supercharged V8 T bucket - his reaction time was better than mine - we were almost level at the end but he was just in front
Then a nice newish white Falcon - beat him
Then another supercharged V8 T bucket - beat him

My last run was against the BMW M3 that I beat last time - he had got a "chip" and some drag tyres
A great race! - he beat me by about the length of his bonnet!

Last event for this season - My device has been on the road for 9 years so its time for some paint and a bit of a rework

I'm thinking about moving some of the batteries into the boot and trying to lose a bit of weight (the car as well)

I'm 55/45 rear/front at the moment - should I aim for 60/40 ???

Any thoughts?
Ask the firefighter to be your girlfriend, throw her either in the trunk or the passenger seat as race conditions warrant.
 

·
Administrator
Joined
·
6,443 Posts
Discussion Starter · #373 ·
[\quote]
Tried something new for the drags - 40 kg of sand in the boot

Made a HUGE difference - ended up with an 11.75

I'm thinking about moving some of the batteries into the boot and trying to lose a bit of weight (the car as well)

I'm 55/45 rear/front at the moment - should I aim for 60/40 ???

Any thoughts?
Sandbag and passenger suggests you're traction limited. Ever go rock hard on the tires and did it get worse or go softer and it got better? In my V8 pinto we ended up with 15 psi in the rear M50-15 but should have used bead locks.

Sandbag also trends towards 50/50 but moving batteries means re doing the cables which would be a can of worms. Could add a couple of ohms and reduce motor power significantly. What happens with 2 sand bags or even 3?
[/QUOTE]
I'm thinking of increasing the voltage at the same time !
Tyre pressures
For the track events I'm using 18 psi - which seems to work
For the drag races I drop down to 9 psi - and I have paint marks of the tyre/rim to check for any movement - OK so far
 
361 - 376 of 376 Posts
Top