I'm looking at building a YB engine for a quick fun track day Cosworth and want it reliable and I want good traction on track.
Current spec; MSD L8 Closed Loop wasted spark, T34.63, AH fab 500 cooler big wing sump and thermostat oil cooler, 6 paddle AP clutch. 6pot 355mm front brakes 4x4 rear, welded diff ,Avo coilovers. Any body that has done track days in their YB RS what am I likely to need to improve on? and what should I avoid?

I'll be putting a 6degree beam on and a Supra diff on when I can, and a Borg Warner EFR 7064 .92 (easy 460bhp and room for improvement), twin scroll exh manifold and A/S inlet are on the wish list for later next year so what injectors are needed for 520 BHP, which Dog engagement box can you recommend and anything else that I need to make the most of the above?

Also can torque be restricted low down if the tyres are struggling and is a higher revving powerful engine better on track better than a torquey engine?

 

First thing I would do is drop to s 3.9 final drive mate

 

With a good aftermarket ecu you can have throttle related boost along with gear restricted boost and traction control so it drives the way you need it to.

Mark

 

Yeah my Emerald K6 does in gear boost control and TC.

 

I have pretty much your current spec.
Changing to :
Link ecu
Bw efr 7064
1000cc injectors
Coil on plug

I already have 6 beg beam, supra diff, and adjustable suspension.
Hoping this will be a good fast track day spec, keep in touch with all those Porsches.

 

If it's 2wd I would also fit a set of 3dr hubs.

And I would use bigger brake discs on the rear to get a better brake balance. With that big front kit the car is not making optimaal use of the rear brakes and the maximal decelleration will be less than original.

 

What porsches are you not able to keep touch with?
Is it just the turbo 911's or some of the NA cars as well?

 

fair comment that on brake balance.

 

Carreras aren't usually an issue at all, it's the likes of the proper GT3s and some older 993 GT2 RS go extremely well.

 

Awesome must be good fun and I bet the Porsche boys love a shonky old sierra coming past em. I can well believe the GT2's go very well indeed. Good hunting

 

The Supra diff is a 3.9. I was thinking that 330mm front discs would be plenty for track use with 4x4 rears, Or will go back up to 300mm 4pots on the rear to suit 355mm 6pot fronts too.

Which ECU would you recommend that has the throttle position and boost as you say Mark?

Is there anything else you'd like to see on a track car, for performance and reliability?

 

Pretty sure Mark would use Emtron

 

What kind of brakes you want on the rear will also depend on the piston size on the front. And of course on the piston size on the rear, especially when you're talking about 4 pots on the rear.

You can calculate the brake balance using the calculator on this link: http://www.tceperformanceproducts.com/bias-calculator/

 

is a welded diff good for track tho - surely that will just want to spin out on tight corners?

 

Welded diff would not be good for track work.

The 3.9 that people are talking about is an LSD or have I missed something in the thread?...just seen it in the original post, oops. Cannot see that being much fun moving the car around in the pits, let alone a very tight bend.

 

A welded diff is only good for dragracing and drifting. You do not want that to go fast.

 

I will look into Emtron then, thanks.
The Supra 3.9 LSD IS Limited Slip NOT welded.

 

Good find thanks, it was over braked on the rear with the 4pots and welded diff so have swapped to 4x4 but will have to do some calculations and see how it feels with the new LSD diff.

Apart from that it must be the ultimate track Sierra right if that's all that was mentioned? No talk of splitters and undertrays, corner weighting, brake balance adjusting, tyre sizes profiles and makes, wheel sizes or lap timers or...