S4 engine/chassis with bespoke suspension onto Guigaro body

[SimonRoberts]

Hi

 

I’m just starting off on a project that I guess has probably been done before so I’d be keen to hear any comments or advice.

 

Basically my plan is to put a later chassis onto a Guigaro body, use an S4 turbo engine/Renault box and put together my own suspension arms, uprights, brakes, dampers etc...

 

I love the shape of the Guigaro body and I want to build something substantially faster than the S2 with the later engine/box and do the suspension myself as this is my particular area of  interest. I've been getting stuff together to do this for ages and now got enough of what i need to make a start.

 

The idea being to make something road legal but fun for trackdays and then maybe do some hillclimbs and sprints at some point.

 

I’ll post some pictures pretty soon J

 

Simon

[Simon350S]

If you want to save yourself a lot of time and hassle and money, just get a post 1985 Turbo Esprit, the chassis are near identical, and then just swap the engine and box for an S4 setup. It will fit straight in.

You can either then keep the standard rear suspension and hub setup and design your own caliper brackets, or change to the later Hub and utilize the factory mounts.

The trailing arm and upper lower links should swap straight over (need to confirm that.

The front suspension design on the post 85 cars is exactly the same as the S4, only very minor tweaks saw the chassis through to the final edition V8 models.

[Simon350S]

Looking at it again. As you are lookin to design and build everything for your suspension then you will see absolutely no benefit to fitting a later chassis.

The later engine & box fit straight in and share exactly the same engine/gearbox mounts.

Why do you any to design your own complete suspension setup for? Just enquisitive.

[andydclements]

Simon R, you'e probably ending up in a similar place to mine. Mine is a Turbo Esprit body on an SE subframe, engine, gearbox etc but I have a S300 head that's been re-worked (larger than S300 valves) which is going on the engine later.

[SimonRoberts]

thanks

 

the chassis i have is from a late 80's turbo.

 

ive really only looked at the front suspension so far and have that designed/partly made but at the moment i'm not sure about the back yet.

 

ive got the engine together and pretty much ready to go in, just sorting the clutch then the box can go on and into the chassis.

 

i'll stick some pictures on later...

 

Simon

[Simon350S]

Look forward to the pics.

If your front lower front suspension is a wishbone then you have the correct chassis as already said so you've got no end to change it.

Andy's car came to him like it is, I almost bought it myself but didn't having gone to see it in Marlborough. Long story, very boring!

Stick with what you've got.

I've got one of the very last S4 engines in my S3T but it's currently running the original carbs and citroen gearbox.

My plan is to swap to the renault box, rear hubs off a late car for the outboard brakes and fit the injection system and chargecooler I have sitting in a box in the garage....

Good luck

[SimonRoberts]

well im doing this as i used to race my S2 and wanted to develope it in the style of the later cars but also change some aspects of the suspension. 

 

i work on race car suspension as my job so it will hopefully be a bit of a showcase for the things i do.

 

Andy - did you have any problems fitting the later SE chassis on? Did everything match?

 

cheers

 

Simon

[Simon350S]

It came with the SE chassis already fitted Simon.

[Simon350S]

Have you seen the Esprit being built up with a fully tubular chassis based on the original, complete with all bespoke suspension arms, uprights etc..... It's a beautiful project and could provide some inspiration for you.

Edited August 13, 2014 by Simon350S

[Advantage]

The dimensions of even a very early S1 and the last of the fuel injected 4cyl cars are close enough not to cause you issues for this type of project. They're no more than millimetres apart at the important areas.

Obviously there will be some fabrication and fiddling required but nothing complicated. Use as much of the hardware from the later car as possible as they just got better with every iteration.

[Simon350S]

https://m.facebook.com/profile.php?id=178516808826230

Take a look at this guy on Facebook, he's the one who's built his own chassis. Some very sexy pictures on there!

If he's designing and building every extraneous component of the suspension system then there surely is no point whatsoever in changing the chassis which is pretty much exactly the same in almost every way apart from the 300sport with its extra strengthening plates and V8 with its different engine cradle?

I don't see any benefit to be gained.

Edited August 13, 2014 by Simon350S

[Bibs]

The chassis changed a decent amount over the years Simon, especially when the Eagle chassis was introduced on the SE.

[Simon350S]

Yes I agree there were alterations but in essence the backbone, engine cradle, suspension pickups front and rear essentially stayed the same.

Any minor alterations would not impact on this project as all of the supension is going to be thrown in the bin and replaced with items that Simon has said he is planning to make to showcase his business.

All I'm suggesting to Simon is that a change of chassis will do nothing more than add cost, time, and a lot of scrap metal left in his garage. It would also mean a grind out of the chassis number off any replacement unit to be re-stamped with his old number unless he's happy to utilize the V5 from the later chassis and any complications that may well bring with its use.

[SimonRoberts]

Thanks for all this...

 

I have the body on my S2 and the new bare chassis on a dolly so best i could measure up suggested they would be a direct swap. Thats good to know!

 

i did plan on leaving the chassis completely alone for this car as the Lotus dynamics engineers are great and i didnt want to turn it into a massive project just to make small changes.

 

Just a few pics of things at the moment...

 

Doesnt look like much to show but i'll keep bashing on!

 

 

[Advantage]

Oh now that's quite pretty. Good effort. It will be interesting to compare NVH levels between yours and a conventionally bushed car.

 

One very minor tip which may help at some point in the future: I know it's all built up and ready to go, but before you stick the engine in the chassis, on the water pump, replace the bolt which is partially hidden by the oil pump pulley with an Allen headed bolt. It makes replacing the water pump in situ so much more simple.

[SimonRoberts]

NVH i'm expecting to be awful but i dont mind that so much!

 

Thanks for water pump advice!

[V8-ESPRITS3]

nice project looking forward to seeing this finished

[iainskea]

Looks great Simon, please talk through your suspension as you go, fascinating.

[Simon350S]

That is looking nice.

One point to note, the original setup was designed to have its castor adjusted using the upper split wishbone and shims on the outer edge.

Do you have the play to be able to do this inboard now or are you planning on changing this adjustment to the lower arm?

[Simon350S]

Cancel that, I see what you've done with the forward leg of the upper wishbone!

Joys of viewing on a phone!

[SimonRoberts]

Ive just drawn up and ordered the uprights that are being waterjet cut from ally... the quote was a bit more expensive than i had expected given that they then need finish machining!  i'll stick a picture up when i get them.

 

Just drawn up the damper brackets for the wishbone and chassis and getting them laser cut and folded - by the end of next week things should look a bit more complete.

 

Planning on putting on Blade ARBs so next thing to do will be brackets for the mounting blocks and then brackets on the wishbones for the drop links.

 

Better do some more work to pay for this!!

 

Thanks for comments.

[SimonRoberts]

 

Right then...

 

A bit more progress! Front uprights are made and just hung in place and everything seems to fit ok.

 

The caliper is a 4 pot brembo off a 7 series BMW and the disc is off a 3 series CSL slightly turned down in diameter. the hub bearing is off a 5 series. the rims are off Tony Gilhams old BMW BTCC car (still pink!).

 

the next step is to design and make the front anti roll bar - the plan is to have a double blade bar with in-car adjustment. i've got the rates worked out to suit the springs so i just need to make them

 

Then to start on the back - i had been thinking of staying with the original Lotus upright but now i'm talking myself into doing my own and changing that trailing arm and going for a double wishbone. it means i can build the Brembo caliper mounts directly into it and make it to give the roll centres that i have in mind etc etc.

 

i'll post some more pictures as i progress.

 

Cheers

 

Simon

 

 

[V8-ESPRITS3]

Excellent! glad to see some updates and looking forward to more.

[Bibs]

Looks really nicely done

[Freemason]

Fascinating project. I wonder if any of the re-engineering on here will be applicable to a stock S2?