Dave_KE30

Video Of Corolla Suspension In Action On Track

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Is that a stock diff in the KE30? No LSD or even welded??

Hi Altezzaclub, it's a Hilux with an LSD and 3.7 ratio. The LSD seems quite strong normally, but obviously on corner exit the inside wheel spins a bit with too much power, but it still accelerates strongly even with one side spinning. Obviously a 4.56 ratio would suit a Beams+J160 better for this type of driving.

 

I hope help the wheel spin with by reducing the weight transfer with increased track and some lowering, and tune with the roll centre and swaybar adjustments.

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That makes sense, I couldn't see a stock one lasting but could hear the wheelspin. Can you wind up the locking of the Hilux??

 

Those suspension changes will make a big difference to the handling, although a stiffer rear sway will pick up the inside wheel easier. Knife-edge adjusters?

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Sorry corollaart,

I didn't see your message. No lighting on the camera, it's just a cheap one from Kmart shooting at 720p 60f/s. I have used a GoPro and a Sony actioncam and I think for the money the Kmart one is great. Because it was cheap I didn't feel so bad putting it in such a vulnerable spot haha. Surprisingly good camera for the money.

 

Altezzaclub,

 

Apparently the Hilux LSD can be tightened up with shims or springs or something, but they wont stay tight for very long. Basically they are limited by design having only 4 or so plates in the LSD, compared to aftermarket ones having more than a dozen (I think the KAAZ units have about 20!). So with less surface area the Hilux ones have a shorter lifespan and are less sensitive. If I did want to change the center I think I would go for a torsen style (Detroit TrueTrac).

 

I'm thinking of the wheel spin as the symptom rather than the cause, with the cause being the amount of weight transfer. Which is where I agree with you that the suspension changes will effect a noticable difference (hopefully improvement). Swaybars are blade adjustable front and rear, although I haven't run the rear one for a while as it made the car slower.

 

I've made some changes to the suspension now, but wont be back at that track until mid June to get some new video.

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Well done vid. Thanks for posting.

FWIW I have used about .5 in /13mm clearance @ 90 degrees to the tire and about 10mm at the top/strut for radials @ 32psi. Also, if they just rub,, add a couple #s of air to reduce or stop the rub. Same with lack of camber ,if you are overheating the outer edge, adding some air will reduce that. The front should do well @ about 3 camber,MOL depending on grip level of the tire and road.

You may also go a bit faster with the inside front tire up about 2in, the weight of the hanging tire gets put on the inside rear tire. It is worth trying a little more front bar in this case. I have never used a factory LS, always welded. The ramp style diff would be nice tho. :)

Of course wider track is better. These cars are narrow . As you add track, the front to rear trim will change.

 

I can't wait to run my new/ old 74 TE27 race car. IT is for SCCA racing in the US of H Production. Iam allowed twin webers, 12/1 compression, and 450 lift cam . I hope to make 150HP,

Is there a similar build some place on this site? Any dyno runs?

My 1.8 VW race car makes 126 @the wheels. I hope that this can do as well .

Thanks for any leads. MM

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Okay, so heading back to the same track this weekend and I'm looking forward to feeling (and seeing with video) how the changes I have made have influenced the car. This is how the car sits now:

 

post-21253-0-43962400-1464699361_thumb.jpg

 

I have installed the negative offset roll centre adjusters (NRCA) which has given an extra 2.4 degrees of camber giving a total of 3 degrees of camber at the front. I have also dialled in a reasonable amount more caster, both changes should be complementary. I removed the tender spring on the front which dropped the car approximately 20mm, and removed the 6mm wheel spacers on the front as the NRCA added 25mm of track and so even with the increased camber the tyres poked just outside the guards with the spacers in. I was running the spacers so that the tyre had enough clearance to the spring perch, so to compensate for the removed spacers I have raised the spring perch up away from the tyre to give about 5mm clearance, so overall the ride height hasn't changed much. Also the NRCA should have drastically moved the roll centre upward, I haven’t yet remeasured everything and plugged it into my spreadsheet but it should influence the amount of roll the front wants to do; having a guestimate I’d say it’s moved up from sump level to somewhere above the crank level. The other thing too is the NRCA has widened the track at the front by 19mm (25mm less the 6mm spacer) plus the extra camber, so now the front is noticeably wider than the rear; this will effect weight transfer). I trial fitted some 25mm spacers for the rear and the tyre wouldn’t clear the body (these worked perfect with a 205/45R16 tyre though).

 

The bad is that I had to cut away the corner of the guard as the increased scrub radius from the NRCA caused interference, however with the increased caster I now have enough room between the rear of the tyre and the chassis to allow an extra 1/2 turn of lock. Steering is slightly harder now due to the scrub radius, and steering feel is a bit vague (which could be a number of things).

 

Another experiment, I slid some o-rings around the shock shafts so hopefully at the end of a race I will be able to measure how much compression stroke I’m using at the front.

post-21253-0-61190800-1464699614_thumb.jpg

Obviously Ignore the Honda plate...It was just a joke haha

post-21253-0-03399600-1464699770_thumb.jpg

post-21253-0-75242800-1464699813_thumb.jpg

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Well done vid. Thanks for posting.

FWIW I have used about .5 in /13mm clearance @ 90 degrees to the tire and about 10mm at the top/strut for radials @ 32psi. Also, if they just rub,, add a couple #s of air to reduce or stop the rub. Same with lack of camber ,if you are overheating the outer edge, adding some air will reduce that. The front should do well @ about 3 camber,MOL depending on grip level of the tire and road.

You may also go a bit faster with the inside front tire up about 2in, the weight of the hanging tire gets put on the inside rear tire. It is worth trying a little more front bar in this case. I have never used a factory LS, always welded. The ramp style diff would be nice tho. :)

Of course wider track is better. These cars are narrow . As you add track, the front to rear trim will change.

 

I can't wait to run my new/ old 74 TE27 race car. IT is for SCCA racing in the US of H Production. Iam allowed twin webers, 12/1 compression, and 450 lift cam . I hope to make 150HP,

Is there a similar build some place on this site? Any dyno runs?

My 1.8 VW race car makes 126 @the wheels. I hope that this can do as well .

Thanks for any leads. MM

 

Thanks for your comments Protec Racing, it seems like all the advice I am getting is point in the same direction which is great.

TE27 are cool, unfortunately the Australian market mostly got K engines in the old Corolla's, and the cars with T engines were usually bigger and heavier hence a bit under powered. As a result not many people are spending money on the push rod T engines here. I used to be keen, I had an old TA22 Celica which I put twin Solex's on, then moved to Yamaha R6 injected throttle bodies and a Megasquirt computer...still wouldn't have made the power of even a stock 4age so I gave up on that haha. Have you got a 2T or 3T engine? You would think 80 or 90 hp/litre would be achievable.

The boosted 3TC that are being used for drag racing though look pretty insane...

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I've made a lot of progress since the original post, substantially improved the car's traction out of the corner with softer rear springs and revised arrangement of the leaves to allow less roll resistance and more droop, added a pan hard rod which improved feel and performance markedly and also allowed for some tuning of the roll to get a nice slightly understeering balance.  

I will soon replace the panhard rod with a offset watts linkage to reduce the vertical movement of the roll centre.  Now the springs are a little too soft to resist axle wrap, and both the leaf springs and the nose of the diff will hit the floor pan if provoked, so I plan to add some lateral links originally for an AE86 to see if I can reap some benefit from those.  

I also found the front springs are just about bottoming out now around the high speed corners, so will have to go for a stiffer rate, probably 300lb/in to 350lb/in.  Anyway here's some videos from earlier this year:

 

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Just a little update, I've rebuilt the rear leaf springs, this time replacing a full length 5mm spring for an 8mm spring.  It doesn't sound like much but according to an online calculator I found the change is from a rate of 145lb/in to 185lb/in; if I ran both additional springs the rate would be 205lb/in so I have some room for more adjustment.  I also had to stiffen the shock and turn down the rear brake bias.

Now the relationship between the front and back springs is: front spring 300lb/in plus a 22mm swaybar, and rear spring is 185lb/in.  The increase rear spring managed to maintain enough of the rear grip from the 145lb/in setup to be happy, with enough of a reduction in rear squat that the car mostly corners on 4 wheels now (compared to 3 or even 2!); this is evidenced by the photographs below from similar corners, you can even see the front wheel to arch gap is reduce with the stiffer rear spring helping to prop up the rear under acceleration and roll. 

Old setup with standard leafs plus 5mm full length leaf:

d57c0f04-9a03-42f1-8409-c29717bfffe5.thumb.jpg.dc7331a90e5bee60861bedb87ce7ad71.jpg

 

Current setup with standard leafs plus 5mm full length leaf:

5a1e68606d7d7_WhatsAppImage2017-09-27at12_40_23PM.thumb.jpeg.c27332323c86bb4bc75931a120d543cc.jpeg

Potential future test setup with standard leafs plus 5mm and 8mm full length leaf combination:

5a1e685acc401_WhatsAppImage2017-09-27at12_40_56PM.thumb.jpeg.c32a3e6846e456be64240d2c5f4a98d7.jpeg

Before:

p2467158288-2.jpg

p2467154502-2.jpg

After:

p2634190438-2.jpg

p2634190304-2.jpg

p2634189505-2.jpg

 

I will be looking to swap out the front 300lb/in 200mm long front springs for some 180mm long 350lb/in springs with a softening of the front swaybar hopefully.

 

 

Edited by Dave_KE30

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1 hour ago, altezzaclub said:

Pretty impressive improvement, photo 2 and photo 4. Must have been exciting in photo 2 !

Thanks altezzaclub, it's definitely getting better based on lap times, and getting more and more enjoyable to drive.  Yeah picking up the wheels looks pretty crazy, and that's a 4th gear corner. I was just a little bit rough on the turn in and gear change and the body just got up a little bit more momentum and managed to pick up both wheels, but from in the car I didn't really feel what had happened.  Below is a video from inside the car:

 

I did have an exciting moment on the first lap after changing the rear leaf spring springs, spinning out on a 150km/h corner after momentarily locking the rear brakes.  It just so happens that I was passing my Dad's KE20 at the time so he got front row seats haha.

 

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