Upgrading stock Seven track days

[O Racer]

This thread was moved from 'parts wanted'

 

My Seven is a bone stock '91 chassis with 1700 AX cross flow, Sierra 5 speed and Dedion rear, I raced other cars over the last 20 years so this car was used sparingly with about 12,000 miles. Sold the last race car and have done 3 track days since late Nov. all at Laguna and have had more fun than I have had 'real' racing in years.So the grand plan...I have a 4/4 Morgan with a non cross flow 1500 and a push-pull 4 speed that has been crying out for an engine swap for 22 years. I found an identical AX based low mileage Super Sprint that needs pistons, machining and assembly. The plan is to put my Seven engine and Transmission in the Morgan as is and do a build out of the new engine, not in any way to full race specs but something more than my stock 130HP engine for some more straight away speed and some more torque for the upgrades where I get pulled. I am down to 1:49 second laps at Laguna on 10+ year old Kumho 185-60-14 radials so with the extra power and 13" race tires I will be even happier

 

I like the idea of a dry sump on the rebuild as Laguna has some high G up and down hill turns

 

I am also still using the stock original brake pads and rotors, that is next in line to change

 

So starting from a stock Seven is like a clean sheet of paper, I want some more speed, grip and handling but not too radical for the street

 

Anyone like to chime in and give me ideas all appreciated.

 

John

 

#18 yellow/aluminum 1991 Caterham Seven

[Croc]

Clean sheet challenge eh? Hmmm

 

I am going to ignore the engine for others as that is somewhat "easy" compared to the rest of the package:

 

- wheels and tires - that seems to be coming together in the other thread. Just keep an eye on how much diameter you are reducing the overall diameter so you can fix it through the gears/diff ratios.

 

- Have you got yourself a good comfortable driving seat that locates you well? Maybe a bead resin seat kit paired with some good 6 point harnesses if you do not have them already? While on safety do you need to upgrade your roll bar from the standard chicken wire version to the FIA/Track day bar which protects you?

 

- Gearbox - go for a T-9 from BGH or one of the other UK engineering outfits that give it a correct first gear and allow you to choose your other gear ratios to match the engine. This should still end up a fair bit cheaper than a Caterham 6 speed box which is nice for the car but really expensive. Ratios will need to be chosen relative to the power band and rev limit of the chosen engine. Gearcalc spreadsheet is your friend here.

 

- Brakes - change the pads for a harder compound better suited to the track but I would not worry about upgrading to big brakes or anything - don't think you will need it since it is all about momentum in our cars. However, if you can justify it I admit I love my Caterham big brake kit on the fronts - I just can stand on them at braking marker one and murder everyone in the braking zone at my local track

 

- Diff - Don't know what final ratio you have, whether it is regular or LSD, etc? Given Laguna is more of a power circuit with some terrain change then maybe think about a diff ratio change at the least to fix the top end speed problem caused by going to 13 inch rims or adding an LSD if you feel you can justify the money. Decision needs to made in conjunction with the final engine choice once you know its power band/rev limit. This is an input into the gearcalc spreadsheet which is linked on this forum somewhere.

 

- how tired are your shocks? If they are then maybe an upgrade to something fresh. Pair this with a good 4 wheel alignment using your new wheels and tires.

 

Not sure you need much more to make the car an effective weapon on track but the driver might want some coaching :jester:.

[Kitcat]

Sooner or later, nearly every crossflow owner decides he needs a BDA engine (or a newer car/engine). They are very expensive ($12-14K?), unfortuately. IF I had it to do over again, I wld do that (even had a BDA spotted for $12K), rather than buying the two newer cars I have now.

 

BBall is upgrading his X-flow and I suspect he has some more constructive/less expensive ideas. I will say that by recently adding just 8 hp, 10 lbs torque to my already powerful Duratec Birkin, via a tune up, I gained a very noticable performance difference.

 

Brakes-stock are pretty wonderful. I changed pads after 20K miles, more because I thot I shd than because it was needed. Given wind resistance, low weight, high cornering speeds and lack of power, the stock Caterham brakes are excellent and need no improvement (IMHO) even for track work which, like you, I have done a lot of.

 

There is a nice CF Tilet seat in the for-sale section here for abt 1/2 what I paid 4 years ago. When I swapped it for my stock cloth Cat seat it really made me feel planted in the car-far less sliding around. Ideal for the track, not as comfy as the stock seats for street use. And 34" waistline, 40" chest size is about tops (it helps to be a shrimp). Caterham also sells a nearly identical fiberglass seat for abt 1/2 the CF version.

 

Have you thought abt a Brooklands screen, with mirrors? When I did that I gained a bit of top speed, acceleration and less cockpit heat. Not cheap tho, a simple wind-deflector, while looking less awesome, also works for less $. You have to add a mirror system to either of those options.

 

Fuel cell? Nice saftey feature. I just added the honecomb aluminum cladding due to cost and occasional stories abt fuel contamination.

 

Ditto a big bright red igintion cut-off switch as a safety feature? Did that one too.

 

New bushings for A-arms etc. Did that one.

 

Did all that stuff (then sold the car, sigh, an up-gradeitis victim).

 

Smaller battery for lightness?

 

Widetrack front end (I have a brand new wide track streering rack I cld let you have for 1/2 what i paid). But then I think you need wider A-arms etc.

 

Ditto Croc's idea of better shocks and maybe adjustable shock perches so you can counterbalance the car? In all honesty, I think Caterham nailed the stock suspension, shocks, narrow track etc. It produces a very neutral, balanced, driveable car.

 

FIA roll-over bar is a MUST, stock is a decoration.

 

Electonic ignition.

 

LSD? With so little power not sure it's needed. And w/open diff, I found my car rotated better on sharp turns-outside wheel had massive grip and it sort of pivited where the inside wheel was sliping, Army tank like:).

 

Happy updgrading! I mite need a 12 step program myself (Maybe Karl and I will start one together:)).

Edited April 15, 2013 by Kitcat

[O Racer]

Thanks Croc and Kitcat, I am going to start changes with tires, wheels and brake pads for the next track day and take it one step at a time

 

The car has a stock cloth covered seat, 5 point belts, has had a single Brooklands screen for years, one Rayodot convex mirror each side and just added a sports racing aero mirror on a 5" stand in the center. I added cycle fenders replacing the clam shells and took off the headlights and indicators as where I live no one seems to care and I still drive it on the street.

 

I have looked into Tillet and bead seats and that's on the list, I am lucky to be 5'8" about 165lbs so I fit nicely in all cars

 

Does the FIA roll bar bolt in? Is it the one available as a factory part from Caterham?

 

If I knew how to add a photo I would. I have a good pro shot from the last event, I am computer challenged if anyone can help on that

 

I will keep posting on my changes and results and continue to ask for help and support

 

Hope to see you at a Laguna or Sears event

 

The car is #18 yellow/aluminum, I am old and gray

 

John

[yellowss7]

 

 

Does the FIA roll bar bolt in? Is it the one available as a factory part from Caterham?

John

 

Yes, Caterham does sell them. You just need to specify whether your car is a dedion or a live axle as they are different.

 

There are four bolts on top that hold standard rollbar on. You will need to undo the shocks as On the FIA bar there is a bolt that goes up into the rollbar from unnderneath. It is a reduced head bolt and you need to becarful installing and removing so as not to round it off. 30 to 60 minute job, less if you are a good wrench.

 

Tom

[rnr]

Hope to see you at a Laguna or Sears event

 

The car is #18 yellow/aluminum, I am old and gray

 

Were you the other Seven pitted by Dave L's Birkin at the last GGLC Laguna day?

 

I will be at the Aug 3 GGLC event at Sears. We also have one at Thunderhill on May 29th

[O Racer]

Here's a photo

[O Racer]

rnr

 

That was me, Ihad a great time...again, I love that car at Laguna, then again i love it anywhere

 

I will skip T-Hill but will definitely be at Sears 8/3-4

 

Which car were you driving?

 

John

[rnr]

That was me, Ihad a great time...again, I love that car at Laguna, then again i love it anywhere

 

I will skip T-Hill but will definitely be at Sears 8/3-4

 

Which car were you driving?

 

I was in a grey Elise with gold wheels. My Seven does not pass sound at Laguna but I will be driving it at both Sears and Thunderhill.

[O Racer]

I plan to stay at the track at the Sears Point event, lets try to met up.

 

When do you think they will open up registration for that event?

[dallasdude]

For safety and performance.....in addition to the the other things mentioned, I woud look at updating the Dedion tube and front spindles and hubs. I think there are 7 revisions of Dedion tubes, and you want to want to check into the latest that will work with your shock setup. Earlier ones are prone to failure, especially with stickier tires and track usage. Running over curbs at the track doesn't help either.

 

If the updated front hub and spindle (2003 up I think) will work with your setup, I would consider that. It is stronger for safety, and from a performance standpoint a good upgrade. The standard Spitfire spindle/bearings hub have a certain amount of flex, which in high speed corners can create pad "knockback", giving you a soft petal in in the next breaking zone unless you do a double pump on the petal. Even with the newer setup keeping your wheelbearings adjusted correctly and in good shape is one of the most important components of the braking system.

If you don't upgrade this stuff before serious track work, I would at least inspect it closely.

[rnr]

When do you think they will open up registration for that event?

 

Reg is typically one month before the event though this one might be a bit earlier as the West Coast Lotus Meet is in Seattle from July 4-7.