Shocks/springs

[davo]

hi

i am after advice on what springs & shocks to use on an'86 gte coupe 400r fitted with an xe lump

also what amount of lowering do i need as i believe the gte sits lower than other models

another thought is,is there a kit which converts a manta to a coilover set up so that adjustment &spring replacement is easier

many thanks in advance

[monzta]

Hi.

No unfortunatly there doesnt exist a coil over set for the Manta.

It is possible to to make one but that is very complicated. The inner wing on the Manta is not designed to take the entire weight of the car. Doing coilovers for the Manta both front and rear requires reinforcements.

The original setup however is very good as it is.

You can get shocks from either AVO, or from SPAX both are adjustable without having to dismount the shock itself. For some reason KONI needs dismounting for adjustment.

This only adjusts stiffness and rebound, not rideheight.

Do you need different ridehight settings for you car ?

I would keep the car at original rideheight (the GTE was some 20mm lower or so, not much). And it would keep the rally look of the 400 car intact as well

[399Road]

Hello ,

Jamex do a good lowering spring kit. My 16v car has these fitted and has non adjustable Bilstein shockers. These Bilsteins are quite cheap and are advertised in Total Vauxhall magazine quite often. I can't remember if it's online autosport or ESP who sell them but fronts were about £40 each and rears were about £30 each. I bought a set of AVO adjustable shockers for my Manta project a couple of years ago and was very unhappy with them. All the top mounting poly bushes looked fantastic but were the wrong size and had to be turned to fit properly on a lathe, The rear shockers lower bushes had the wrong size metal tubes through them and all of the shockers started to rust after a fortnight! This car hasn't even driven yet and closer inspection of the new shockers reveals that they have no primer under the paint! at £250 for a set of 4 you can see why I'm not happy. I thought I was buying the best at this price but obviously should have bought Bilsteins. I've also removed my rear Anti roll bar and this has improved the cars handling . You can now drive quicker out of bends without all the understeer I had before. So I'd say for a decent set up buy Bilstein shockers, Jamex springs and remove your rear Anti roll bar but don't chuck it away- you might need to refit it at MOT time if the tester notices it missing! One last thing... I've recently polybushed the car and would say one of these bush kits is worth every penny. Good luck with suspension mods and don't forget about resetting your wheel alignment after. It needs setting up differently on a lowered car and your front wheels will need to toe-out slightly instead of toe-ing in as standard ride height Mantas do. Luke.

Edited January 21, 2011 by 399Road

[davo]

thanks for the advice

polybushes are already on the shopping list !

i found a tigra that i used to race handled better without the front anti rollbar in the wet

has anyone tried gaz shocks?

i found these a good shock for the money when i was racing

[opel2000]

Very interesting reply there by 399Road.

I too polybushed the 4rse end of one of my old manta's and found a huge difference in handling.

Also,,, out of all the springs I've fitted over the years I've found Jamex to be a huge cut above anything else I've fitted, on my first Manta (my old 1.8) I fitted a one inch drop progressive rate Jamex coils and new Monroe shocks, and the car was quite possibly the most suberb driving Manta that I'd ever had, in fact would go to say that it was possibly the most suberb combination of comfort and handling over any car I'd had, but just a bit too much daylight between the wheels and arches for me though.

Second best were the Jamex 70mm drop fitted onto my old Red B and then later went onto my V8 which got sold on............ Not only are these coils still going strong but with such a huge drop they were not coilbound as so many aftermarket springs are, and there was a surprising amount of comfort for a coil with such a huge drop in coil height.

Thirdly I would say that the Coils I got off of TJM on this forum (TJM Motorsport) were an equal to the 70mm Jamex coils as they gave a good ride height but more comfort than the 70mm lowered Jamex.

Not 100% sure but I think these were AVO Springs.

Wish I could remember the name of the springs I fitted that weren't even a year old when the both rears broke on me when getting the tail out on some bumpy track, they were a very very well known and respected brand but would not touch them with a barge pole again.

[399Road]

Cheers Davo,

My mate Rob bought some Gaz shockers a couple of years ago for his Manta A. There was a bit of messing about ordering them as they listed the Manta A as having the same shockers as a B/C/CC etc. Manta A's have very short front shockers so he had to measure the old ones and have some made to fit. Once these turned up they fitted properly, came with poly bushes and worked very well. His car is in bits again at the moment having 16V conversion done and being polybushed with Powerflex (I think) bushes.He says he had to buy a full Bush kit for a B and has a few bushes left over that he had to do with Dr Manta's new Rubber bushes.

Has anyone else tried removing the rear Anti roll bar to make the car handle better?

Edited January 23, 2011 by 399Road

[madmantamik]

to add to the previous posts my friend who owns huddersfield mini spares always uses GAZ shockers and springs on all his cars including some serious bussa powered cars he says that for the money they are faultless.

also i have never tried removing the rear ARB but i did run two front ARBs as i prefer the nose to stay as neutral as possible to prevent the rear wheel lifting as i did not have an lsd

[Christ]

Heard of removing the rear ARB but haven't figured out the physics of why it should be better

also thought about doubling up the front one just to see if it improved things at all.

The adjustable AVO shocks I've got have been fine, bought 2nd hand I returned them to AVO who refurbed them and had no problem with fitment.

And another vote for poly bushing the car, feels much better now everything's where it should be

[Kevin Abbott]

Billys are the best thing you can put on a manta, i had jamex lowering springs on my coupe back in the day and found them to be coil bound no matter what orientation.

Spax shocks were a pain to set up, too hard or no rebound after that.

I don't know about anti roll bars ( speak to the rally gurus.. spewy, titmuss ect about them)

A lesson here........

My mate Gorgon who has spent £££££ on his Manta came over to me, he said " Kev, drive my car and tell me what you think"

It drove s**t due to the brakes and the original bushes..

I took him down the road to Dannys and his standard gte,( Dan has poly bushed his GTE) Dan took Gordon for a 'spin' in his car.

Gordon came back, he couldn't believe how Dans manta went around corners, Gordon doesn't scare easy but Dan scared the s++t out of him.

Lesson is, decent shocks and springs with quality bushes will out perform a big buck engine manta, the manta in original guise will beat the s..t out of you

[mantadoc]

10 years, 100K miles and still fine - bare in mind my suspension setup is an evolution that stopped me wrinkling windscreen pillars, grinding off the towing eye etc and losing a fair amount of gearbox..............

[399Road]

Hello,

I had a book a few years ago about rally Chevettes and this said that the H.S rally cars had the rear anti roll bar removed to promote oversteer as the cars understeered as standard. I don't know how true this was but I tried it on the Ascona and it made a really big difference straight away. I ran the car like this with my first" open" diff and now with the LSD fitted. The back end of the car doesn't seem to pitch or roll as you might expect it to. I can also come off roundabouts or out of tight bends faster than before without understeer. Luke.

[Retro Power]

The rear roll bar removal is mainly helpful because it reduces the rear wheel actual spring rate, and a LOT of mantas are too stiffly sprung at the rear. Many of the "lowering kits" also raise the rear spring rates, and this knackers the driveability completely on our rough roads.

The rear roll bar basically gives a raised spring rate in single wheel bump (i.e. most of the time) and removing it drops that rate again, with no great tradeoff in terms of roll, as there is no weight on the rear of a manta to control really.

The big key to handling is always remembering the "tail and dog" situation with the rear axle, when the sprung weight is not a huge multiple of the unsprung weight then the job the dampers have to do becomes very difficult, as they don't know which "end" they are trying to control. The only answer really is to run a very soft setup.

[davo]

thanks for all the advice,but what about the ratings of the springs front & rear?