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petert

[Race_Prep] Never Ending Race Car Build

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petert

500lb pounds, at the wheel. It has a turreted rear end. I hear what you say about E85. The motor I'm building is 12.8:1 so I thought I may as well give it a go. 100 RON is expensive and difficult to source, whereas E85 is $1.20/L and at the pump. I'll still run 98 as well with the aid of a flex sensor for long distance events.

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petert

Wheel alignment, balance and new AO50's this week as well. All set now for the upcoming race season.

post-2864-0-66366300-1484375883_thumb.jpg

post-2864-0-31254300-1484375915_thumb.jpg

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JeffR

Good luck to you and John this year. Hopefully you can mix it with Parry. What about Adrian, Cam & Pat's 205's? Will they be doing the series too?

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petert

Adrian is also doing MRA. Parry is doing the Wakefield 300 with us. I suspect Cam & Pat will focus on supersprints initially.

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camgti

Nice work Pete

 

We are aiming to be sprinting by somepoint around march. Couple thing have come up for both of us but we are almost there.

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andy0075

In Austria it is the other way round. you can buy 100 RON everywhere but E85 is difficult to get ;-)

My motor has 12.5:1.

 

I will try this season ~400lb/in meassured direct at the rear wheel but without turreting the rear.

no ARB or std. ARB. I have to try what is better.

 

Why is the car so heavy ? Regulations? My 205 has Race ready 750kg.

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petert

That includes driver. Car still has original doors & windows. It would be nice to be lighter. 400lb is too light for slicks or AO50's. Currently have no ARB but we are going to do some testing before Race 1 with various size bars.

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andy0075

Hi Peter,

 

Have you already done some testing with ARB and what size? I have now 500lbs/in on the rear wheel and no ARB. But i have to wait till 22.04 to do some testing how this setup will work.

So maybe you have some results ;-)

 

Andi

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petert

Yes, tested no ARB, 22mm and 25mm. The later was best, which means we're going to remove it and try some 600lb springs with no ARB next.

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B1ack_Mi16

Cams too big for the valves. They touched.

 

I think the valves in my head for the 2.3 engine must have been sunk a bit into the port (36.5mm inlets and standard 29.6?mm outlets)?

But everything was a bit unschrouded on this one. I run fairly high lifts at TDC (3.8 / 3.25), but yours are of course lifting a tad more.

 

What rpm do you recon you would see max power? With mine the power kept rising all the way to the rev limiter at 8000rpm.

So that way I believe my cams are too wild for the application as I don't dare more than 8000rpm on the 94.5mm stroke.

 

CIMG0830.jpg​

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petert

I'll probably impose a 8500 limit in the interests of reliability, regardless of the peak. I ended up getting it to work with 4.5/3.7mm lift @ TDC. Careful attention to valve clearance and turning down the exhaust valves to 29.5mm resulted in 0.035" between the valves. It would always be easy with a slightly smaller inlet valve and a standard exhaust valve.

 

Also, the 140kW peak in the graph was at 8200. We forget to reset the rev limiter. It's now at 7600.

Edited by petert

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andy0075

Thanks Peter for the info. I will mount my GoPro under the car to film the rear suspension and how it works.

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petert

I should also add that we wound the shock rebound all the way up, which further suggests stiffer springs are required. It was completely neutral with those settings. It wasn't very supple on ripple strips however, thus the need to wind off some rebound and fit stiffer springs.

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petert

Looking forward to the first Supersprint of the year this Sat. I've fitted new heat treated, soft Yoko A050's all round - 205x50/15 on the front and 195x50/15 on the rear. I was going experiment with rear spring rates but have run out of time.

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petert

What's not apparent in this thread, is that it's been two years since I drove my car for one reason or another. I've been letting my son drive in his races. I was stunned today on lap 1 how different it has become. Since early 2015 we've fitted a new engine & dry sump, new adjustable front control arms, new negative camber rear arms, revised spring rates a few times, pedal box and quicker steering rack. I almost completely lost it on lap 1 turn 2, not expecting it to turn in so well and much quicker with the new rack. I can not believe how well it handles now. It is simply on rails.

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JeffR

You seem to have adapted quickly to its new characteristics because when I checked live timing you were only a tenth or two off John's times.

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petert

He ended up beating me by 1.2 secs. He was looking for a top 10 finish but 13/88 is excellent. Most of the top 10 were tricked Honda powered Elises or Exige V6. Twelfth was an STi. Nobody got near the Stohr WF1 however.

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petert

Here we go again. Increasing the rear springs from 500lb to 570lb. Hopefully we'll be able to run a light ARB or better still none at all.

post-2864-0-95838600-1491899915_thumb.jpg

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welshpug

what does that translate to in wheel rate?

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petert

570lb

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welshpug

surprised you even need a roll bar at all then :lol:

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petert

With 500lbs, 25mm was an improvement over 19mm, which was better than none. Thus bigger springs necessary and hopefully none.

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andy0075

Last weekend i had my first race this year after i have built "something" that makes the rear much more stiffer compared to 23mm TB's.

I have now 90N/mm springrate meassured on the wheel combined with a 25mm ARB and the car handles brilliant.

Rear toe is ~zero and camber ~2°.

 

Here is the promised video : https://youtu.be/pRTQ6yCQmg0

 

But you are right. If you want to completely remove the rear ARB you have to go way stiffer at the rear.

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petert

Nice work. We ran yesterday with 570 and it was definitely better. Next meeting 650.

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Andy

Slight thread hijack here but as the conversation is centred on suspension spring rates, what is the agreed wisdom on rea r torsion bar diameter for a strictly road going 205 in , weight wise, standard trim and coilovers at the front with spring rate of 150lb/inch. And if this is rather like asking how long a piece of string is, I will shut up and go away.

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