Guy Croft Lada Riva Twin Cam replica

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badlyworntoy

Re: Guy Croft Lada Riva Twin Cam replica

Post by badlyworntoy » Sat Jun 08, 2013 12:20 am

Right folks thats it now, time to stop polishing and doing magazines and get down to using this car for its intended purpose.

quick update :-

First track day in it at Croft circuit Darlington threw up some intresting scenario's regarding performance. Car was fast but we really struggled with brakes, I just couldn't slow the car down enough at the points i Needed which meant I had to scrub speed off with engine just to get around without going off. The standard lada brakes were actually on fire at one point....Full brake upgrade needed, work is in progress on this.

I was also hitting a big hole in the torque curve of the engine due to shifting up a little to early from 3rd to 4th gear, and also running with the wrong final drive didn't help any with this. I think maybe I should build another differntial and move away from the 3:9:1 which Is far too high for track use and maybe go back to the Lada 1300 ratio of 4:4:1. I really would like to use 4th gear a lot more as I spent all day in 2nd and 3rd gear.

I think I need to do lots of re engineering.

Tommi and my fellow Lada fans your thoughts please.

Nix
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Urbancamo
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Re: Guy Croft Lada Riva Twin Cam replica

Post by Urbancamo » Sat Jun 08, 2013 11:53 am

I didn't notice until now that you have backing plates behind the disks. They limit air flow around the disks really badly. Get rid of them no matter what brakes you have now or future. They are never used at any race car.
I commonly see cooling ducts for front brakes too.

Also do not expect HC performance from 20 euro brake pads. One manufacturer wich always works is Ferodo, also available in Lada brake pad from (tip for all Lada owners reading this). Both DS2500 and DS3000.
DS3000 compound is commonly used in national level rally cars in my country. It bites hard even the disk is glowing red hot.

Did you test rear brake regulator settings? It must be set at full or really near that in track conditions, otherwise plenty of braking power is lost. I would say Lada rear brakes are putting more than 25% of total braking power.

What it comes to braking force, imagine F1 drivers putting 100-150 kg's of pedal effort from corner to corner, lap after lap. And their consentration to driving don't change at all...

I already quessed right you have encountered the typical problem with gear ratios. Gear ratios in the Fiat gearbox are exactly the same than Lada gearbox. From 2nd to 3rd it drops from 2.1 to 1.36 wich equalises around 2000+ rpms in revs. And it's a lot. It also stresses to synchroniners really much especially in faster driving because the gap is so huge. There is a lot job for tiny synchronizers.
To rise up 3 and 4 to driving gears you must shorten the rear gear ratio a lot. 4.44 is the fastest OE ratio, but there is also 4.7, 5.1 and 5.3 available. You can use those handy online calculators to see wich suits the car and track conditions best.

-Tommi
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Guy Croft
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Re: Guy Croft Lada Riva Twin Cam replica

Post by Guy Croft » Sat Jun 08, 2013 12:04 pm

Phil Ward wants the car in Auto Italia - FB him

G
Guy Croft, owner

ace124
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Re: Guy Croft Lada Riva Twin Cam replica

Post by ace124 » Sat Jun 08, 2013 1:44 pm

Don't go throwing your brakes out without trying a proper race pad.
I think you will be surprised what a good pad can do.
In relation to ratios....Im having a batch of 5&6 speed dogboxes made soon.
Ill post details in the sale section soon. You will have a choice of ratios, all will feature
1:1 top gears. These are for Fiat 124 / Lada type gearboxes and can handle lots of torque.
There will be straight cut or helical gears for quiet running.
Oh....and they will cost 1/3 of the price of a bacci romano 5 speed dogbox.

Btw. Car looks awesome!
Last edited by ace124 on Sat Jun 08, 2013 3:45 pm, edited 1 time in total.

Guy Croft
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Re: Guy Croft Lada Riva Twin Cam replica

Post by Guy Croft » Sat Jun 08, 2013 2:50 pm

You will have to do extensive (installed) prove-out before offering them for sale, here anyway...

G
Guy Croft, owner

ace124
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Re: Guy Croft Lada Riva Twin Cam replica

Post by ace124 » Sat Jun 08, 2013 4:00 pm

The gearboxes are tried and tested. They are made by a company that makes them especially for circuit race and rally cars.
And has done so for many years. They are not made locally.
Racing Lada's is very popular in some eastern European countries.
They prefer to make them in batches. Ive ordered 5+ at this stage. We have one
here complete. 3 are sold, pending deposit, so 1 or more left for any interested people.
Ill pm you details before i post anything for sale here for your approval.

Guy Croft
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Re: Guy Croft Lada Riva Twin Cam replica

Post by Guy Croft » Sat Jun 08, 2013 5:27 pm

OK - understood.

Nix is on a 131 5 spd not a 124 box btw.

G
Guy Croft, owner

badlyworntoy

Re: Guy Croft Lada Riva Twin Cam replica

Post by badlyworntoy » Wed Dec 31, 2014 7:15 pm

Folks

It’s been a long time since I’ve thought about updating this thread, but I feel that with these few spare hours I seem to have found myself with late on a very frosty night it may be a good time. I’ve said before I can’t seem to ever run out of energy and enthusiasm with this old Lada, so maybe it’s a good time to tell you all about the current spec and what my goals are still with it.
As you know it started out as a replica of the famous Top gear Lotus Lada (which G.C was involved with) and I only ever really intended it to be a toy car and to maybe have a bit of fun with on a weekend, we have done two magazine features, one with Retro cars and another with Phil Ward’s excellent publication of AUTOITALIA but this was long ago and I kept yearning towards the true potential of such a special car. To my delight the development seems to have heavily snowballed over the last 18 months or so. I started a small Motorsport business with a Ex Professional Racing driver. We tested this car HARD lap after lap around Croft Circuit in Durham, setting brakes on fire, tearing engine mounts and even de-laminating tyres etc it’s very easy once you start to get into the dynamic and design of Ladas to see the potential lurking within. If you add some knowhow a lot of time and some proper engineering to them they can show a show a clean pair of heels to most things on circuit.

We started to do more and more track days with it and each time we made heavy upgrades to the car, in particular the Brakes, gearing and suspension and each time the Lap times would fall, sometimes by as much as 3 seconds. The ultimate lap time in a works touring car around Croft Circuit is a low 1:20 and when I first ran this car we were struggling to get below 2:05 now we are regularly achieving the Mid 1:40’s and my ultimate goal is to go sub 1:40, This would be a very respectable lap time for a car weighing over 1 tonne with hardly any-no aero work and running fully analogue N/A 8v engine with traditional technology found in 1970’s production cars.

You can imagine the trouble that is caused when you start out braking Lamborghinis and driving around the outside of Mitsubishi Lancer Evo’s in a Lada, they walk over and expect to find some sort of mod sport special disguised as a Lada with some unacceptable Japanese turbo nutter expletive_deleted engine with loads of numbers on it, but their grief it compounded when you open the bonnet and say “no its just a Fiat twin Cam on a pair of IDF’s”

I posted some interesting pictures below of some the upgrades and the car in action. They is also some YouTube inboard videos of the car to enjoy. It also gives some of the people who haven’t experienced the performance of one of G.C famous Fiat Twin cams a chance to gauge the performance and sound these engines generate on full chat, obviously the videos dilute the feeling of speed but they the best thing from outside the car. I apologise that I won’t be going into details on all the pictures as it would take me months to do, but if they is any key technical questions I’d be happy to answer them for you.

I’d also like to thank a few key individuals that have made this project possible, whom without we wouldn’t be able to achieve anything like this level of performance in a Lada

Tommi Huuhka, who’s help with differentials and general level of knowledge and advice on all things Lada would have made everything so much more difficult.

Jackie, my general number 2 who is there helping out with everything on this car from Logistics to sweeping the floor

Juhani Tormanen, Juhani flew over from Finland to build up a Close ratio Gearbox for us, his knowledge and confidence inspired us all....top bloke in every respect.

G.C, obviously for the engine and general advice on everything.

Max Wakefield, Max is a world champion on 2,3 and 4 wheels and knows how to work a set of controls, his input from the cockpit is totally invaluable....No way could we extract everything he does. A very knowledgeable, experienced and consistent racing driver.

An earlier video below of the car in 2013, the camera and sound quality is poor but it gives a good indication to the performance prior to the close ratio gearbox and race final drive I fitted. Its impressive as its managing to keep up with a Lotus Exige

https://www.youtube.com/watch?v=v2IEdo9tSpM

A much later Video from September 2014, here you can see Max taking on two Caterham Academy cars, Its a shame about the gear selector falling apart as I was keen to see him get close enough to the yellow one and pass it. This Video is great if you have never experienced one of GC Fiat twin cam engines on full chat, the sound quality is excellent as are the cameras from the Racelogic data logger. I apologise that the camera is on a bit of a wonk and that the airbox lid is rattling slightly but it doesn't ruin the video.

https://www.youtube.com/watch?v=9UK6lhaU9WI
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zdrafko51
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Re: Guy Croft Lada Riva Twin Cam replica

Post by zdrafko51 » Mon Aug 03, 2015 12:10 pm

ace124 wrote:The gearboxes are tried and tested. They are made by a company that makes them especially for circuit race and rally cars.
And has done so for many years. They are not made locally.
Racing Lada's is very popular in some eastern European countries.
They prefer to make them in batches. Ive ordered 5+ at this stage. We have one
here complete. 3 are sold, pending deposit, so 1 or more left for any interested people.
Ill pm you details before i post anything for sale here for your approval.
Hello!
I have been working on something similar. I will start a thread when we download all pictures...

For now I have a question. Ace124 what torque can this gearboxes handle and what is the price? And for badlyworntoy can you tell me how much did you pay for close ratio gears or complete gearbox, I don't remember what you bought from Finland (I have one OE Fiat 132 gearbox)?
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