new picture of my GD T70 on track

Chris M · 20th October 2009, 07:44 AM

nice new picture from last friday on track with my GD T70 which (touch wood) is going very well at the minute. probably my last trackday of this season though now with winter looming! roll on next season.

Mark · 20th October 2009, 08:40 AM

WOW, that's fabulous. Are you going to compete with it next year or trackdays only?

Johan · 20th October 2009, 09:36 AM

Really nice !

Chris M · 20th October 2009, 09:58 AM

i've done two small club sprints already (non msa) and placed 4th and 5th overall out of 40 cars (barkston heath sprint track) so that was satisfying as the tight twisty track isnt really suited to it. next year all being well i want to start hillclimbs and sprints, possibly the Isle of Man Classic 3 day event if all goes well as a start event.
other than that it will be just trackdays etc rather than circuit racing, i'm not keen just yet on paint swapping on track and also not sure what if anything it would be eligable for in terms of circuit racing.
its been a long journey as the car span a bearing last year after 3 events and required a new short motor, and then this last month the clutch let go at silverstone trackday in spectacular fashion, so its not had enough use yet!

Chris M · 20th October 2009, 10:01 AM

Quote:

Originally Posted by Johan

Really nice !

thanks much appreciated!
did you get much racing done this year Johan?
best event of the year for me as a spectator was the silverstone classic, my first ever visit and a must for next season for me.

Johan · 20th October 2009, 10:04 AM

Yes I had a good year and feel fortunate in today's climate to be able to get out there and enjoy the cars.

Ron Earp · 20th October 2009, 10:50 AM

I'm liking that! Looks great, do you have more shots of the car?

Chris M · 20th October 2009, 11:19 AM

Quote:

Originally Posted by Ron Earp

I'm liking that! Looks great, do you have more shots of the car?

thanks Ron. i think i posted some links previously to some build pics on photobucket, i also have a couple more recent ones i need to update from this season which i've attached. i'll try and find the photobucket link as it has some build pics but not all.

Chris M · 20th October 2009, 11:31 AM

a few build pics etc.
GDT70 Lola pictures by chris-T70 - Photobucket

domtoni · 20th October 2009, 11:54 AM

Great video, I'll bet with that motor the car really flies !!!

Dom

Tom · 20th October 2009, 09:47 PM

Chris,

what size front tires are you running?

Tom
GDT70 under construction

Paul Thompson 'Hooligan' · 21st October 2009, 05:29 AM

Looking great Chris...

I too am looking forward to next year and hopefully taking part in more events, inc possibly the odd race now I have my license.

As this year, it is very much going to be dependant upon other competition preparation works but I would very much like to be in for the Manx Classic again next year - fingers crossed.

Dalton Veitch · 21st October 2009, 06:56 AM

Why is it not suited to the short, twisty bits. It looks nimble and grippy. Is it large and powerful (compared to clubman type cars) and more suited to power circuits?

Dalton

Chris M · 21st October 2009, 07:36 AM

Barkston heath is a very narrow track with little run off in certain spots and you can barely open it up , similar at teeside autodrome, altho saying that the car did place well in the sprints so i'm maybe a bit ott. it does however fly around places like croft and silverstone where i did trackdays this year.

tyres- tom i'm using 255/40/17s up front on 9" or 10" rims (cant recall off top) and rears are 335/30/18s on 12" rims. using toyo 888s at the mo which are great in the dry etc but not so good on standing water.
how far on with your build are you?

Chris M · 21st October 2009, 07:38 AM

teeside last friday has an uphill double bend which was fairly hard work at low speed due to the tyre sizes and lack of power steering, at speed the steering is well weighted. i just need some arm strength for 1st gear tight bends lol!

The Baron · 21st October 2009, 07:57 AM

Hi Chris, what was the reason given for the spun bearing in the LS6?

Chris M · 21st October 2009, 11:18 AM

the spun bearing was my old engine (ls1) which i bought second hand, as a bit of an unknown quantity. i put a cam, new chain/sprockets etc and arp rod bolts in and fitted a dry sump, and did 3 trackdays before it span a bearing, and was using 6500rpm. 2 bearings picked up and marked the crank quite badly.
i then ended up with a weber race engine from the states with a forged LS6 bottom end when the dollar was poor against the £ for a bargain price! currently using that with my ls1 heads on etc.
touch wood the engine seems to be fine and working ok now.

Chris M · 21st October 2009, 11:20 AM

Quote:

Originally Posted by p thompson

Looking great Chris...

I too am looking forward to next year and hopefully taking part in more events, inc possibly the odd race now I have my license.

As this year, it is very much going to be dependant upon other competition preparation works but I would very much like to be in for the Manx Classic again next year - fingers crossed.

hi Paul
by hook or by crook i intend to be at the IOM sprints, either competing or spectating if i cant get an entry. let me know any plans for going over if you'd like company! :-)
regards
chris

The Baron · 21st October 2009, 12:33 PM

Quote:

Originally Posted by chris-GDT70

the spun bearing was my old engine (ls1) which i bought second hand, as a bit of an unknown quantity. i put a cam, new chain/sprockets etc and arp rod bolts in and fitted a dry sump, and did 3 trackdays before it span a bearing, and was using 6500rpm. 2 bearings picked up and marked the crank quite badly.
i then ended up with a weber race engine from the states with a forged LS6 bottom end when the dollar was poor against the £ for a bargain price! currently using that with my ls1 heads on etc.
touch wood the engine seems to be fine and working ok now.

I believe there can be a couple of oiling issues with the LS series a) dependent on the cam used and if it's hydraulic there doesn't seem to be an issue but if it's an aggressive flat tappet in an aluminium block there can be problems with the lifter bores. As with any engine pulling 'G's' there can also be a problem but the dry sump should cope with that however, b) there have been some oil aeration & foaming issues which result in bearing problems. I believe Corvettes have suffered from this when running track days, but GM seem to be replacing engines under warranty and fitting a modified version of their stock dry sump system.

One of the symptoms is the oil pressure differential between cold starting and hot running so that's something to look out for. It is surely fixable but I think it needs some careful engineering in the oiling dept. If your pressure is dropping to around 30 psi hot running from a cold starting reading of say 60 psi, then you could be in trouble in the twisty bits.

Hope this helps. Back in the day I ran quite a few Chevy's and Fords and there wasn't the knowledge in the UK unless you went to Mathwall (cubic money and even their products weren't foolproof) so lessons were learned the hard way...

Tom · 21st October 2009, 01:13 PM

Chris,

The chassis fabrication and assembly is pretty much done, the engine tuned etc. Still a have to do alignment and weight balancing. Now have to finish the bodywork, which will be polished gelcoat. Have already finished the doors and the dash hoop, will work on the front and rear clips next.

For tires I am also using Toyos in the same size, though they are RA1s. Was a little concerned about getting the 255 under the front bonnet, but you did and looks amazing.

With regards to the last comment on LS oiling problems, the issue on LS7s was traced back to the oil tank - early models lacked both capacity, as well as adequate de aeration measures. So many of the engines that blew were getting fed aerated oil. A drysump expert I spoke to also said that the stock gerotor pressure pumps are not great at really high rpm because they work at crankshaft speed, and are not geared down as external pumps are. Above some threshold (mid 7000s?) the stock pumps are apt to start cavitating

Tom