242GT 1979 Group C Race Car

peterwgpa said:

A couple of more jobs for the list. Going to fit a set of 4.11 gears in our LSD. At present we have 3.91.

Also we had moved the overdrive switch to the dash from the slide switch on top of shifter as hard with gloves to slide the switch. We only use overdrive at a couple of tracks and at the last meeting I was having to take hand off wheel and glance to find switch entering the fastest corner on the track which I found less than ideal.

At present considering using a clock spring arrangement to get a paddle shift or even 2 switches mounted on Momo steering wheel hub to select overdrive and run the later overdrive relay arrangement instead off the earlier version.

The ultimate - Works drive setup but way too pricey for this task

Or more likely this route

Or the stock later model Volvo knob with the button would also work. We already have a wiring harness and relay for it.

Bit still to ponder before we decide on solution

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If you want a quick solution for the overdrive button, use a 245 wiper stalk and wire the o/d into the wash button on the end. I did this to one of my 240's and it worked great. I did have to go to the '81 and up relay setup though, as it is a momentary switch.

Rob

Thanks for the idea Rob

....can still remember the sound of the old Paul Newman/Tulius C-Production TR6's using the OD to split 3rd and 4th gears running at Road Atlanta 40 years ago....

Decision has been made. We are going to use the horn button via a relay to turn overdrive off and on as it can be reached by thumb on either side without removing hands from wheel. Thanks to hiperfauto for relay and wiring info for our plans. Greatly appreciated.

Of course it was not wired up when I checked as we did not bother to as horns were removed on assembly. We will have to pull wheel to see what wiring is where but will be easily sorted. Just getting last parts of later model overdrive setup together. Got the harness and just have to get a relay now

Like your observation MH!

Mechanic called today and delivered the good news that I did not burn out a valve or worse by running too lean. Rest of work progressing.

Have sourced a good second hand 4.11 crown wheel and pinion for the LSD from a local diff specialist which will be fitted in place of the 3.91 we have at present once we get car back with balance of work completed.

I am going to do the Overdrive changeover to later model relay setup and other mods myself. Now have all the parts ready to roll.

peterwgpa said:

Have sourced a good second hand 4.11 crown wheel and pinion for the LSD from a local diff specialist which will be fitted in place of the 3.91 we have at present once we get car back with balance of work completed.

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I originally started with 3:91's in my track car. Eventually switched to 4:11's. The 4:11's were faster at most tracks. I'd switch out to 3:91 for Sears Point Raceway though. The 4:11's always had me wanting to change gears mid turn at that track. Fine everywhere else. I kept the previous 3:91 shims and R&P to swap in a few days before I went there. Wasn't bad at all.

Thanks Tuff. Yes we are keeping the 3.91's too as may be more suitable for 1 or 2 tracks. We have tighter tracks closer to home which we think will suit the 4.11's better. Trying to replace shortage of horsepower with some gearing to see if we can get some closer racing. Worth a try and we learn more as we go.

Should get car back next week. Everything has been fitted and fine tuning has begun on the dyno and the tuner is comfortable with the link to the UTCIS and has the software links all sorted. We have an issue with the fuel distributor and as they went to fit the spare reco unit we had in stock a check prior to fitting revealed the plunger was siezed for reasons unknown. It has been sent off to be repaired and at the same time is being modified to deliver a little more fuel for top end. Once it is fitted up they will tune the UTCIS to deliver the fuel we need across the rev range and we will then get the results of the dyno.

Due to take it out for track testing in a couple of weeks which will reveal the drivability aspects of the changes made.

We are going to hold off on changing the diff gears to allow us to measure the cam and fuel system changes first. Also gives the bank account a rest for a moment too.

Dyno results in. 135rwhp or just over 100rwkw and a nice healthy fuel/air ratio right across the rev range. Was hoping for a little more (only based on what I see quoted elsewhere but hard to get a like for like comparison). Taking it out Saturday for a test on track so lets see what the drivability feels like as that's more important than outright horsepower.

Be nice to have the car back home.

peterwgpa said:

Dyno results in. 135rwhp or just over 100rwkw and a nice healthy fuel/air ratio right across the rev range. Was hoping for a little more (only based on what I see quoted elsewhere but hard to get a like for like comparison). Taking it out Saturday for a test on track so lets see what the drivability feels like as that's more important than outright horsepower.

Be nice to have the car back home.

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B23? Seems about right for slightly more compression and a k or similar cam.
If you're running a B21 like the GT's got in the USA, that's pretty good.

Our biggest improvements when trying to squeeze out more hp from these basically stock class limited motors was cam timing (can you use an adjustable cam gear?), fuel psi adjustment and ignition timing.

Tuff.

B23E. We have adjustable cam timing fitted. Tuner has not been too agressive on timing adjustment as he has had to pick a spot that gives us right air fuel ratio accross the whole range. He said we have a little more to be unlocked via timing but have held back waiting for the set of 020 injectors to turn up so we will fit them and then see what else can be found by adjusting both at the same time. Fuel distributor has been tweaked and our guys think its maxed out with next option going to a 6 or 8 with closed off outlets.We have also had to play nicely within the rules and not take heaps off the head to bump up compression beyond a reasonable range. KG8cam. Will be interesting to drive it with the KG8 cam verse K that we swapped it for.

Car picked up (thanks and great work GLT service centre Capalaba) after having the KG8 cam (supplied by us) and the programmable UTCIS WUR (supplied by us too) fitted along with a dyno tune to tweak the air fuel ratio across the RPM and Vacuum range. Took it straight out to Queensland Raceway to track test the results of the changes. Here is my opinion for what it is worth.

KG8 cam. I had done my own research and on buying the cam it was suggested it would benefit via bigger valves than standard sizing fitted to head and it would likely need more fuel than standard KJet could deliver. It was also known to come on song above mid 3000 rpm range. Well we got it the air and fuel it needed and got a better overall rear wheel horsepower number but the drive out of the corners was awful and lap times suffered. Result KG8 cam coming out and H going back in as we cant alter our valve size under rules we run. With our valve size constraints after driving both cams on the track the H just feels more competitive in allowing the lower powered heavier Volvo a chance to catch up some ground in the slower sections of the track. Like I said my opinion only for our purposes and constraints and driving style.

We also changed standard Volvo clutch fan for an electric fan. On track temperature yesterday was over 40 degrees Celsius and car ran 20 degrees cooler than ever before. It is acknowledged that the better fuel delivery may have also contributed as running leaner can up engine temperatures too. Was very but pleasantly surprised by difference in operating temperature and testing on such a hot day means we should never have an issue due to cooling system capabilities.

In short before next outing H cam back in along with a set of new injectors part number 0437502020 (2 sourced from England and other two from Lithuania)and yet another tweak on dyno to dial in right fuel/air ratio given changes. Then leave it alone and go and run it.

peterwgpa said:

On track temperature yesterday was over 40 degrees Celsius and car ran 20 degrees cooler than ever before.

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That'll help a bit managing timing/mixture....

Spoke to Mechanic and tuner this week to make a plan and to check assumptions and we are good to go. The last 2 injectors also arrived so we finally have a full set.

After talking with tuner it confirmed our own experience and very happy with the aftersales service from UTCIS for the programmable WUR. Australia is a long way from USA and with different time zones in play we were impressed at speed and quality of reply so he was able to get software up and running and questions answered quickly. We are very happy with the service received. The tuner has it all sorted now and stored with his other software so its just plug in and go once the injectors and the old H cam is fitted.

The KG8 camshaft has been on sold already.

So the confirmed work for late March is

1. Remove KG8 cam refit Volvo H cam
2. Fit 4 new 0437502020 Bosch injectors
3. Fit AEM fuel air ratio gauge as well as an analogue feed from gauge to an Innovate motorsport LM-2 Air Fuel ratio meter that we will use to record what's going on when out on the track. The gauge is a quick visual and the LM-2 will be used to record races. The LM-2 a little over the top especially since we are going to have it dyno tuned for set up but will be good to monitor ongoing performance and operation without the need to take it back to a dyno regularly. Going to mount the gauge on the roll cage using an autometer pod. Decided against changing it out with the fuel gauge in the R sport gauge cluster and to keep it seperate.
4. Fitting the later M46 overdrive harness with the relay switched from the horn buttons on the Momo steering wheel.
5. Dyno tune it to account for new injectors and cam. Tuner has advised he will be able to unlock a little more HP via timing as others have suggested above now we have all planned components in fuel control system checked, fitted and ready to go.

Track test at a sprint meet of all changes will be early April and hopefully just drive it all season long without a need for anything much apart from preventative maintenance. Yes I can dream

GLT service Centre looked after us extremely well and we picked up the car today and its ready to test on 09th April. H cam back in along with the new 020 injectors, later model overdrive harness with relay and the overdrive on and off wired to high beam stalk (we don't need for lights) to make it easier in the heat of battle so we can leave hands on the wheel. Our Momo horn buttons not functional so switched to stalk solution instead. Could have likely gone for a later model push knob but lets face it not as exciting and I like the original 1979 knob in the 1979 car anyway.

Also fitted an AEM air fuel ratio gauge shown below (apologies for photo quality) and we also now have an Innovate motorsports LM2 recorder wired up ready to go when we want to monitor what's happening air fuel ratio wise. Its mounted in the glove box. We only fitted one Bosch 4.9 sensor but the tails to join to the gauge or the recorder are side by side in passenger foot well and we can plug and unplug as needed. Initially I was going to run an analogue feed from AEM gauge to the LM2 but we were advised not possible by others that have tried and failed before even though the instructions say it is possible. Plug and unplug is very workable.

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After our next outing we will fit our replacement UTCIS WUR which is on its way from USA and we will dyno tune it again and tweak a little more to see if we can squeeze a little more HP out of it then it will be ready for next race meet in June.

Coming along nicely Peter!! Look forward to hearing how the first (next) outing goes. When I was racing SCCA, in my class we had to have our headlights in place, but taped up. So didn't matter if they worked or not. However, my horn was functional. In fact, I put a louder one in (technically illegal). Amazing how often I was able to use that to create a bit of irritation for a competitor that I was quicker than, but having a difficult time getting around. Nothing like sitting on their bumper mid-corner and blowing the horn at them! Get out the way.....

Track test today. Was nice to get back behind the wheel

Extremely happy with way it went mechanically but we had a couple of electrical gremlins we have not seen before with Temp gauge and Oil pressure gauge going haywire in session 1 then Tacho joining in in session 3 too. Certainly got my attention when I took a glance at gauges to see Oil Pressure gauge reading zero but low pressure alarm was not sounding and a glance at temp gauge also had it at Zero but backup temp reading and alarm was all good and car was running strong so no other tell tales matched so pressed on.

Fuel pump relay stopped working coming into pits at end of session 2 (very convenient for a change) and car would not start. Diagnosed it as fuel pump not working so checked fuse and all good so went to backup spare relay and still no good. Then proceeded to our Fuel Pump relay Yellow to Yellow red bypass wire for very first time and bingo fuel pump fired to life and we finished last session on bypass.

The overdrive switch on high beam worked a treat as easy to get to with both hands on the wheel but with the electrical gremlins we had it failed to work intermittently at same time.

We had instrument cluster out while we wired in the air fuel ratio gauge and fitted up the later overdrive relay and other modifications so we will go back over our work and see what the cause is and rectify it. That's why you track test to iron out the bugs.

Heres a pic at track

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We attended our first race meeting for the year and did the 2000km road trip to compete in the Sydney Speedfest at Sydney motorsport park on the weekend.

The car is finally sorted mechanically and we had a trouble free run all weekend with only tyre changes and normal preventative checks needing to be done for a days practice and two days racing.

Unfortunately the weather was ordinary and we had a wet qualifying and two races with wet and dry conditions and thankfully the final race was dry. I am not used to racing in the wet so was slow and our wet tyres were way too old and hard and had no grip. The joys of budget racing but drove to conditions and skill and kept it on the track. A lot didn't and there was quiet a deal of damage across all racing categories.

Next race meeting is in August but we are running 2 sprint sessions before then for some more seat time and Kris my partner in the car running some sprint sessions too.

Couple of pictures and a youtube link to some footage. Our race category covers a broad ranage of Group C and Group A cars from the early seventies till 1992 with the fastest being the 1992 Nissan GTR's.

Track Shot photos courtesy of Phil Bush who worked at the dealer back in 1979 when the car was prepared for Bathurst race.

6am after a 3 am departure for 12 hour journey to get to track to unload ready for practice Friday

Coffee stop number 1 - 1 Degree Celsius in down town Warwick

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Thursday night arrival after a wash down. It rained on way down and car was filthy

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In the pits with Wets fitted

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Pit shot because you can

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Dummy grid for wet qualifying. Lets just say 5 plus year old wet tyres have no grip. Does not rain much where we live and when it does normal club type events get cancelled so my second ever motorsport day in the rain. May sound crazy to some but that's the part of the world we live in.

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Another pit shot with the brand new intermediate wets in background which we purchased just in time for it to dry up. So brand new for next time assuming they don't go hard before they get used. Should have put them on for race 1 on Sunday as we all went out on slicks and track was as wet as so life was very interesting. More of a road rally tyre but that was all we could get at very short notice in a price range somewhere near our budget.

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Dummy grid

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Some action shots

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Some you tube footage for file out of category to warm up lap

https://m.youtube.com/watch?feature=youtu.be&v=usNIKkxQo-E

Some on track footage

https://www.youtube.com/watch?v=RR2hEklUKZM

And home safe and sound ready for next weekend


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peterwgpa said:

The car is finally sorted mechanically and we had a trouble free run all weekend with only tyre changes and normal preventative checks needing to be done for a days practice and two days racing.

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That's great news and a true testament to your hard work!

Glad you had some fun and made it home all in one piece.

Many thanks

May well it continue!