Lotus 7 S4 1974: light restoration and modification

Lotus 7 S4 1974: light restoration and modification

Author
Discussion

uglyduck

17 posts

137 months

Monday 17th March 2014
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Here is a shot of the 1970 Lotus 7s4 GT at the Canadian Historic Grand Prix in 2013. This was my first race weekend and my first outing in the car

7s4whatelse

156 posts

167 months

Tuesday 25th March 2014
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As you said before: Your car, your rules. Personally I would prefer it "quiter" -
Knut, good progress so far!!! will be interested to hear how the rearaxle behaves under such big load.

anp

23 posts

220 months

Tuesday 25th March 2014
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Nearly done now

Just the seats to recover, propshaft to fabricate from the one I have and extend the steering rack shaft I am working on chassis assembly at the moment but cant decide on the route for the metal brake pipes

I know from the master cylinder it travels along the lhs chassis rail and drops down into the coupler where this is fixed I don't know I do know the position of the front flexible connection but not the rear

Can anyone advise me please

Thanks

Paul

Farlig

632 posts

151 months

Wednesday 26th March 2014
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Kghaas said:
To do, or not to do?
mindre er mer....

Farlig

632 posts

151 months

Sunday 6th April 2014
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1966 Lotus 38, Indy 500, his holiness Jim Clark wink

ETA - http://www.oldracingcars.com/Images/nelson/Lotus38...


Edited by Farlig on Sunday 6th April 21:31

mickrick

3,700 posts

172 months

Monday 7th April 2014
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Nice smile I like the mirrors too wink

Kghaas

Original Poster:

173 posts

150 months

Monday 7th April 2014
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Farlig said:
1966 Lotus 38, Indy 500, his holiness Jim Clark wink

ETA - http://www.oldracingcars.com/Images/nelson/Lotus38...


Edited by Farlig on Sunday 6th April 21:31
No, its not that one....but it was nice smile


Mirrors:
I used some aluminium soldering on the mirror stays. Worked briliantly smile
The mirrors is also part of the livery...

Today I welded up a cross-member. This chassis is a 1300 chasis, which doesn't have the round tube under the engine. I have made one, and it turned out ok. I planned on making it removable, but it was just too easy to weld it in place.

Edited by Kghaas on Monday 7th April 21:36

Farlig

632 posts

151 months

Monday 7th April 2014
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1968 Lotus 56 Turbine, Indy 500, Graham Hill wink

http://fotos.subefotos.com/833672cd2f9c50a90beb9d4...



Edited by Farlig on Monday 7th April 22:05

Kghaas

Original Poster:

173 posts

150 months

Tuesday 8th April 2014
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Spot on!

Farlig

632 posts

151 months

Tuesday 8th April 2014
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Nice!

7s4whatelse

156 posts

167 months

Wednesday 9th April 2014
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Knut, - are you going "turbine" now?

Edited by 7s4whatelse on Friday 11th April 06:21

Kghaas

Original Poster:

173 posts

150 months

Saturday 12th April 2014
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No turbine, still Duratec 2.0 with ITB's

I have now been on my first 1 hour drive with mapping. Some first impressions:

1. Type 9 gearbox is nice
The gearbox is a standard Type 9 previously fitted to a K series Caterham. It is also fitted with a short shift and extension turret.
It is much smoother to operate than the 4 speed and the short shift makes it more fun to change gears. I have extended the gear lever which I also feel give a much better feeling. Having 5 gears makes the car much more comfortable. It is a perfect upgrade, but it is a lot of job on the S4...

2. Microsquirt with autotune function is nice
Microsquirt works realy well, and the autotune function tunes the VE table as you drive. After 15 min, the car is now all sorted in the cruising range, and it is only above 6000rpms which I have issues.


3. ITB's= fast response
The throttle is now a very much on/off switch. I will have to get used to it or see if there is something in the tune which can sort this out. On a track you wouldnt care, but for street it just too aggressive.

4. Duratec is powerful
There is a lot of power in the engine. It pulls from 700rpms in 5th all the way to 6000rpms where I currently stop. If you change 2-3 gears down and floor it, it really goes. Mind that this is currently in mapping mode so I cant be too wild..

5. Exhaust is too silent
I made up an 2" exhaust with only one silencer. My initial fear was that it would be too loud. It isn't. Its too quiet. I can still get some sound, but not the xflow scream and backfires. Maybe I will have to go to a 2.5"....




delavay

7 posts

123 months

Sunday 13th April 2014
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Hello everybody ,I'am french ,my car is a lotus 7 S4 n°3068GT 1971 .
So I have a probleme to slave cylinder hydraulic cluch ,it is the same to triumph spitfire ?
Thank you . Delavay

7s4whatelse

156 posts

167 months

Wednesday 16th April 2014
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Hi Delavay,

- which exact problem do you have with the clutch? There are several issues and therefore solutions

kind regards, Hajo

Is your 7 stiil green with the yellow "nose"?

Edited by 7s4whatelse on Wednesday 16th April 17:03

delavay

7 posts

123 months

Thursday 17th April 2014
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Hi 7S4whatelse,
My propleme is the slave cylindre clutch (girling 7/8") destroyed.
Slave :Girling 64673347 A8S1 Master : Girling 625 A (ok)
where can I buy one on the siteweb ?

Thank you so much
Delavay

delavay

7 posts

123 months

Thursday 17th April 2014
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My S4 . original color : orange
cool

7s4whatelse

156 posts

167 months

Friday 18th April 2014
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Hi Delavay,

- easiest way for this parts is to contact Redline (Mick Lincoln) - http://www.redlinecomponents.co.uk/

From own experience I can highly recommend them.

Edited by 7s4whatelse on Friday 18th April 08:43

Kghaas

Original Poster:

173 posts

150 months

Wednesday 23rd April 2014
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Duratec mapping second impression:

1. Remember to set rev limiter!
The Duratec is very rev happy, and when tuning the higher rpm band it is easy to over do it. I hit 8239rpms at the most. Huge fun, but lucky the engine survived. I had sett all the criteria for rev limit with both soft and hard cut, but forgot to activate. oops..

2. The afterburner is back.
I had a complaint about the Duratec being too quiet. I take it back. Using the rpm band between 3000-7200rpms (where the limit is now set) the engine is noisy enoguh and has a lot of bangs and crackel on decel. Huge fun!

3. The Duratec is powerful
My first impression was that the Duratec is very powerful low down, and has a very useful torqe down low. It is very cruiser and town friendly. On top of this I can add that the Duratec is a screamer from 3000rpms and up and is seriously fast. The power comes on very smooth and is very controllable. If you floor it in first at 20mph it will spin on dry tarmac. Haven't tried any other gear

4. Chassis is stiffer
I added a chassis brace, and the car feels much stiffer on the road. I actual think there is less body roll, but then again it might just be that it is 6months since I drove the car last.

Had a real blast today and got thumbs up from a few motorcyclist. They probably wish that had a Se7en smile
This is the last update on this thread for a while.




Farlig

632 posts

151 months

Thursday 24th April 2014
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Well done Knut - enjoy now the weather´s getting better too wink

Kghaas

Original Poster:

173 posts

150 months

Wednesday 11th June 2014
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Small update:

Changed to Mintex 1144. Way better brake balance
Did a trackday, and was measured at 104db. Limit on the track is 100db, so the scrutineers let me out on the track to do a drive-by test. Got the green and managed to do 42 laps (each lap is 3,2km).

Car works very well. did half of the laps with Brooklands aero screens. Didn't really feel any different but I was driving without doors all day.

Engine and gearbox works really well. I guess the engine is about 160hp area. Future plans are rollbar and free flow exhaust.

Edited by Kghaas on Wednesday 11th June 19:43