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Opel Manta V8 Rally Car


rutthenut
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Proper LSD will make a huge difference as locked diffs push on a lot I'd try that before any other mods to the set up. An enthusiastic "chuck" can also overcome a welded diff but as the diesel advert says "only the brave" :)

Not sure of the advert, but definitely know about the severe push - that is most definitely the worst thing about this car, by a long stretch.

The increased camber made the car a bit better on road-type bends, but this weekend's event was nearly all 90-degree bends, which really highlighted the understeer, especially with icy roads too. Even if brave enough, chucking the car in a scandinavian flick was not really an option as you need to get some turn in to do that! Handbrake similarly of little use. Best approach seemed to be to use the engine braking and dropping clutch on change down into a corner. That got the back unsettled and sometimes moved how I wanted in some places but I would need much more practice to make that a reliable approach.

Have a plate-type diff in my Strat and know how much difference that makes. Just a matter of cost to sort out the Manta axle :-(

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  • 2 months later...

Following on from discussions in another thread, did some digging to find photos of my car in it's previous ownership, rallying circa 2008

Driver: David Todd, Nav: Ben Perry

http://www.ianhardy.net/gallery/main.php?g2_itemId=89793

http://www.ianhardy.net/gallery/main.php?g2_itemId=89639

http://www.ianhardy.net/gallery/main.php?g2_itemId=76124

http://www.ianhardy.net/gallery/main.php?g2_itemId=76108

http://www.ianhardy.net/gallery/main.php?g2_itemId=73359

http://www.ianhardy.net/gallery/main.php?g2_itemId=73351

Also some of Dan Hart, with Rob Hardy on the Roger Albert Clark rally

http://www.ianhardy.net/gallery/main.php?g2_itemId=71548

http://www.ianhardy.net/gallery/main.php?g2_itemId=71662

Plenty of other Manta action shots taken by Ian Hardy, try a search from this page http://www.ianhardy.net/gallery/main.php

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  • 4 weeks later...

Did some prep work on the car last weekend for an MOT in the week and spotted rack gaiter split. Those aren't in stock at local motor factors, so put car through MOT anyway. That's all they failed it on. Now have the parts and need to fit them for a retest within the next week and a bit.

Was a bit of hassle when putting the car onto their ramps, an exhaust clamp got caught on their under-body lift and pulled the exhaust off the downpipe. Oops. They thankfully sorted that out, realigning the pipes and fitting new clamps. Then it would no longer tickover reliably, which was resolved by a blast up the main road and back, plus a battery jump pack which got the voltage to a level that meant the engine did not cut out on tickover. New battery required to sort that out.

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  • 1 month later...

Have done a few of the minor jobs on the car since that last event, as I am due out at Abingdon again on 8th June.

It now has the sump guard fitted and exhaust seems better protected, so would hope that avoids problems on the bumpy grass section that knocked the pipe last year.

A set of rally springs have been fitted, which raise the car a bit from the old set and give a bit more compliance. Still running the old Spax gas dampers though.

New Bimarco seats fitted, old Sparco seats sold on fleabay for a decent price. Put a couple of belt cutters in the car (an MSA requirement this year).

Did more work on fuel pipework, pressure regulator and filter location (now in the boot).

Radiator fan now controlled by a thermostatic switch, so I can't forget to switch it on. Haven't done so yet but was always a risk.

Vacuum advance unit replaced with one that works and now connected with a vacuum pipe. That seemed to help some of the running issues but it still doesn't pull all that smoothly. Certainly not how I'd want or expect a V8 to response to the throttle.

Still have the same minimal silencer on there (which results in my ears wringing after a one-hour spirited drive on the road, oops).

For rallying, I will need to refit the exhaust insert to get it within the noise limit. Last year, that was much more effective than I'd wanted or expected, so now it has some holes drilled in the insert to try and reduce it's effectiveness. Sure it also strangles the engine, so a different silencer should be a future change to put in place.

Have some more tyres to go on the various (14") wheels, as rear set show a lot of wear (from that locked diff, particularly) from not many actual miles. In future, I'd really want to go up to 15" rims and get a better choice of tyres and greater widths.

I've got little free time in the next few weeks - as ever - so although the car is technically rally-ready, I have pretty much the same list of improvements and tasks I would still like to work on between now and then. This includes:

Rolling road session to try and sort out the poor running. Also to get power output readings with and without the exhaust insert, just to know current levels.

Moving fire extinguisher bottle. I now have the right pipework to do that, plus it will need fitting of new pull cables, if I get round to it.

Increase front camber and add (more) toe-out, if I can, to try and reduce the understeer a tiny bit.

Adjust damper settings to full soft at front and full stiff at rear. Slight chance I may buy a set of Bilsteins, which I very much want on the car, before the event.

Tweak tyre pressures for more front grip and less at the rear - might use the naff road tyres at the rear on the event, keeping the better tyres on the front, if I still suffer with major understeer.

Oh, I also need to get a tow bar fitted to our replacement Heep, so that I can tow the rally car to and from the event :-o

Sorry, no photos of late, other than the brake pads that fell apart when I took the calipers off to do the steering rack gaiters

13922936656_20c55101a6_q.jpgBad Pads

Edited by rutthenut
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  • 10 months later...

Sorry, let this topic go completely stale. Must try harder!

 

I got another finish at Abingdon, but had a varied assortment of problems on the event (that's rallying).

Misfire began at start line of one of the longer stages, which turned out to be a plug lead came off - that really did hamper the engine performance. Fuel starvation on occasions due to tank not having any anti-surge baffles or swirl pot/tank. Bent a wheel on another longer stage, tyre then deflated going into a fast 90 right. Quick spin with no damage done but then needed to fit the spare. Scissor jack worked ok, albeit stiff to use, when raising the car, but it didn't want to go back down again. Easy solution, push the car forwards off the jack. Plenty of time lost to those problems (excuses, excuses) and otherwise still did not feel that I was going well enough. Braking still has little affect on the rear, despite new shoes, cylinder and bleeding. Handbrake cable does not do anything, so auto-adjusters cannot do their job, which means shoes cannot be set up well enough. Solution will be a disc brake conversion.

 

Also unhappy with the engine, which has poor pickup on wot from low revs, hesitance and some misfires. Having read all of the potential issues with the Lucas 'Prince of Darkness' electronic injection system with the 'Flapper' design, I took the decision to ditch those parts rather than chase problems with old components of poor design.

 

I have now fitted the MegaSquirt engine management system, using 'hotwire' injection components (no flapper) and EDIS electronic ignition with twin coils. That certainly resolved the poor running issues of the old system. I hope to write up a bit more about that some time, albeit not a common Manta topic.

 

Before converting the injection/ignition system, I did put the car on a rolling road to get some figures for 'before and after' comparison. On the old setup, the car was producing max power of 177bhp and 200lb/ft of torque. Handy figures, though not all that exciting. There was a noticeable dip in the lower rev range and it also tailed off rapidly at high revs (Rover V8s do not rev well anyway, with standard valve train). Figures with the exhaust silencer in place showed a bigger dip at the low rev point, and about 5-6bhp less. So not too detrimental.

 

I have yet to get it back to the rolling road for an 'after' figure and some tuning of timing and injection.

 

Next event I did, with the MegaSquirt system in place, was the Regency Stages at Bath & West Showground. Another event consisting of many short straights and 90-degreee bends. Using first and second gear, with plenty of welly, to try and steer from the rear, ended up boiling over the engine at the end of the stage. Time enough between stages to cool and refill but problem continued. Had to then change driving style to use higher gear and lower revs, which in turn meant more of the dreaded understeer, and somewhat less fun.

 

Cooling system to be investigated further, as well as an open-diff axle to have a disc brake conversion hopefully to be fitted to the car soon. With MOT looming, a hunt around underneath has shown some areas in which rust is making itself known, so that needs addressing as well :-(

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Before converting the injection/ignition system, I did put the car on a rolling road to get some figures for 'before and after' comparison. On the old setup, the car was producing max power of 177bhp and 200lb/ft of torque. Handy figures, though not all that exciting.

 

Readout of that rolling road session can be seen here

https://www.flickr.com/photos/rutthenut/17039536955/

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realy did not like anything over 4-4.5k did it. has the megasquirt  system helped higher up the rev range when you drive it. did you get to the bottom of the cooling issues.are you going to get a lsd soon, i'm no expert but i'm sure you would probably lose alot of time on acceleration out of corners and the start line with a open diff even with entry improvements.

Edited by MicsManta
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This is a 3.5 engine, standard cam, etc. Originally from an SD1 though now using Range Rover 3.9 intake manifold, injectors, fuel rail, trumpets, plenum and airflow sensor. Ignition was Rover spec too, now totally electronic with no distributor.

 

Torque on the graph readout was at least fairly flat from 3000 to 4000, fwiw.

 

Engine feels more responsive to the throttle throughout the rev range and does seem better at the top end than it was before. Reminder to self, must ensure that throttle linkage does give full throttle since changed over.

 

I've not used it since that November event, for various reasons. Hope to get out for a blast tomorrow to remind myself what it does go like, then perhaps take it into work for a day or two ;-)

 

Be interesting to see how different the power curve may be now. Hope that the dip won't be there, and that it should continue further up the rev range (intake is a lot less restrictive now, as well as having better control of fuel and sparks). Would also hope to see higher maximum numbers too, of course, though driveability and throttle response the major aim for the conversion. The car does sit at tickover much happier now too, although that is no help for stage times ;-)

 

Cooling still to be investigated further - may have been air causing localised hotspots if not bled out. Old setup had heater in the circuit too, so may reinstate that soon (will help with demisting, at least). I will try and find out from Rover types as to whether the bypass is still needed when running with no thermostat, though did that before the engine change too. I did get some heat management issues when playing around in low gears at Bruntingthorpe 'ASDA On Your Marks' charity day before. Think the radiator is large enough and thought it was clear, as no problem at all at speed in hot weather. Water flow is most likely the problem, as temperature differential between top and bottom hoses is quite high, indicating it takes too long to go through the radiator - possibly because more flow goes through the bypass hose; I think that's only needed when a t-stat is fitted so will see if it is ok / safe to restrict or blank that off entirely.

 

LSD still very much on the 'want' list, but looks like some chassis welding going to be a priority. Will want to fit an adjustable bias pedal box too, and then be able to ditch the servo, with the rear disc kit going on there. Do expect that the car may spin up an inside wheel with the open diff, which can affect cornering behaviour and potentially time. But being able to negotiate the chicanes might counter that.

 

The replacement axle has a GT/E diff ratio; I'm not sure what the existing axle has, though think it's the same. For an LSD, I would like the higher-geared/lower ratio from the 1.8 as top-end speed right now would figure at about 140mph and that is way over what I'd need when rallying.

 

Have got an swirl pot and extra fuel pump, which I will probably fit before next event. Would rather get the fuel tank modified to put a baffled sump below it with new inlet/outlet connections, but that is more expense and specialist work to arrange for someone else to do,.

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  • 1 year later...

Sorry no updates on this for a long time.

Car got an axle with higher ratio / lower-geared 3.9 diff and an lsd unit fitted into it.

Also Astra rear disc conversion (from Retropower) with balance-bar pedal box (ditched the servo)

Various odds and sods as is common with competition cars, nothing too major.

Different set of stiffer front springs on the car, new bushes for front lower wishbone

 

Then I went and pushed a straw bale out of the way on a rally this weekend :-(

A big, wet, straw bale weighing well over two tonnes. Front brakes failed as I approached a tight 90 left, so knocked off very little speed from initial 80mph. The bale was punted quite a way from the road. At some cost to the front of the car...

Early exit from this rally

 

Got a bit of work to do on the car now. Cut off front end and fit a new one, new wings, bonnet, anti-roll bar, headlamps, radiator, oil cooler, remote filter, alternator bracket and so on. Not even found out if subframe, engine mounts or any other serious parts broken yet :( And cause of failed brakes to be sorted out too. Whilst at it, replace doors (both have rust, one has dent from being t-boned in a rally earlier this year), new poly door windows, rusty rear arches to be replaced, 400 bootlid and spoiler. And the list goes on!

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