Tyres for my project

[ArnieVXR]

I'm putting together my Monaro VXR with a high-spec (1000fwhp) 427TT and a 4-speed auto. It currently has big brakes (APs) and 19inch rims. For those who don't know, Monaros need extensive modifications to run tyres wider than 245s, which is a problem I need to overcome.

I want to run the odd RWYB on drag-radials. I'm led to believe that I should be able to get into the 9s with 1000fwhp, auto, IRS and 1700kg. This will only achieveable with wider rubber.

So the question is how wide a drag radial will I need? This will drive how far I have to go tubbing the rear-arches and the mods for the rear suspension (I'll be keeping the IRS). I should be able to find 17-inch rims that fit over the brakes, so MTs are a possibility.

Ideas???

[ArnieVXR]

Or can I get into the 9s on R888 Toyos (18inch 335 profile)?

[Geoff Stilwell]

Just putting fat tyres on doesn't mean your gonna run 9's. Everything is in the set up, such as the axle ratio, the right gears in the box and just because an engine puts out a 1000bhp doesn't mean 9's. SO let assume you have a 1000 on tap. Is the box going to be strong enough? Is the axle strong enough? Have you set the suspension up right so the car leaves the line right? Before you go down the line to far i would suggest you try the car out first and see what it does. Then start making the changes...because as sure as eggs are eggs you change 1 thing and it will have a knock on effect.

[ArnieVXR]

John Sleath is assembling/tuning the engine and has built the gearbox for me. It's a LSX427 block with AllPro billet 6-bolt heads and some expensive forged internals. I'm running BW s300 turbos. The gearbox is a modified 4L80e. John's confident that this combination will push 1000fwhp. He's also putting a prop together, so that covers everything back to the diff. I'm using a FAST management unit to control both engine and gearbox.

I appreciate that the back end is where much of the important stuff happens on the quarter mile. There's a guy on the Monaro forum with 1000fwhp that was pulling 13's on 275 road tyres, while another guy ran a UTE with 380bhp and drag radials down in the 11's.

I know I need to tub the car, as 245s will be useless on the road. I'm just wondering how far to take it. I've seen a Monaro running 345s, but haven't seen any drag radials in that size.

Apologies for sounding like a noob with a chequebook, but sadly that's what I am right now

Once the car is up an running, I'll be looking at what it takes to achieve my goal. I just want to avoid rework.

Cheers
Arnie

[Toyless]

Surely John can advise on this ?

[Benni]

Congratulations Arnie !
This seems like a fine car to me, will it still be street legal ?
In which class are you planning / wishing to run ?
What is "fwhp" ?

[ArnieVXR]

Toyless said:

Surely John can advise on this ?

He's told me to stick with the IRS, as the alternative won't corner and I'm interested in running it around RAF Marham (they run charity weekend trackdays twice per year and the runway doubles as the back straight). I get the impression I keep asking John 'how long is a piece of string' questions. He's very patient with me, which is good as my questions are all over the place. I think my brief is probably too broad: track days, standing quarter and standing mile.

[ArnieVXR]

Benni said:

Congratulations Arnie !
This seems like a fine car to me, will it still be street legal ?
In which class are you planning / wishing to run ?
What is "fwhp" ?

Thanks Benni. Yes, it will be street legal. I can't wait to blast passed a few exotic sports cars when it's done

I don't know much about drag racing (other than a few trips to Santa Pod to watch). I'd like to just try out some RWYB until I get the hang of it. If I take it further, I'll buy a 'proper' drag car.

FWHP = flywheel horse power. The Monaro forum is keen on the difference between flywheel and rearwheel, as most don't have the engine out on dyno days.