Guest Neil Russell Posted March 8, 2004 Report Share Posted March 8, 2004 My ma lovingly purchased the new speed pro book on uprating and tuning the TR6 for my 33rd Birthday on Sunday. I have been reading with great interest, concentrating mainly on the brake, diff and rear end section. Opinions please: The book states that the Salisbury Ltd slip diff can handle lots of power. Considering my engine in road going trim will be putting out 380 - 400 hp at the flywheel when installed, do people think that the following mods will be enough: Salisbury Ltd slip diff, Modified Cosworth steel driveshafts and steel Cosworth Hubs. Helicoiled trailing arms, Trailing arms machined and fitted with Roller Bearings. Vertical Shock conversion (The TR Bitz one is already on the chassis?) and Anti roll bar , not sure which yet. Bearing in mind that this is going to be a road going show car and not blitzing around a race track do people think these mods will be strong enough. I would value the opinion of the racing fraternity in particular who may have experienced failures and modified around them. But all comments as always are welcomed. Neil. Quote Link to post Share on other sites
jean Posted March 8, 2004 Report Share Posted March 8, 2004 Neil, I like your ideas of uprating your 6, but keep in mind that the chassis members are made a rather thin steel, and brackets already now tend to brake out/off with the power available from a normal PI engine ??? Jean Quote Link to post Share on other sites
Richard Crawley Posted March 8, 2004 Report Share Posted March 8, 2004 Niel, no experience with the sort of mods you are proposing but get the trailing arms thoroughly checked out & crack tested before you shell out on any machining work. If they have had a hard life (&most have by now), they are prone to cracking on the webs where the main arm casting meets up with the hub unit casing. This can lead to a major failure with a rear wheel stuffed right up inside the wheel arch or in some cases ripping off altogether. I believe the cracks are caused by years of “bottoming” on the rubber suspension stop due to those crappy lever arm dampers. Quote Link to post Share on other sites
Andy Moltu Posted March 8, 2004 Report Share Posted March 8, 2004 Is using needle rollers a good idea? Would uprated polyurethane type bushes be a better bet? If you get any sort of sideways impact (such as a kerbing) on the wheel there is going to be no give in the trailing arm bushes and presumably a greater risk of cracking the trailing arm. Quote Link to post Share on other sites
Guest Neil Russell Posted March 8, 2004 Report Share Posted March 8, 2004 The Book makes for interesting reading. I think crack testing is definitely a must, having said that mine looked pretty good with no scrapes etc and I did helicoil everything. The car chassis is currently running poly bushes, but the book recommends the change to needle rollers in high power applications because apparently even the nylon ones distort. But is a certain amount of distortion a good thing? Jean, I am not so worried about the chassis. This was comprehensively re-built with brand new trailing arm mount sections and brand new t-shirts Its as strong as it needs to be in that area. My big worries are in eliminating the spline locking problems and building everything strong enough to resist the torque in the back end Obviously if I can get away with off the shelf go faster bits then this will be all the better. What does a fully specced 2.7 litre racing TR6 put out at the flywheel?? Are new trailing arms available? or are we all going to run out of second hand ones eventually? Neil. Quote Link to post Share on other sites
Richard Crawley Posted March 8, 2004 Report Share Posted March 8, 2004 Are new trailing arms available? or are we all going to run out of second hand ones eventually? I also "Helicoiled" mine as a matter of course because I was not prepared to trust the original casting tappings but to answer arse about; yes they are a finite resource. Knowing you’re posting history (& obvious engineering capabilities) I would probably look at fabricating my own steel units, or get someone to do it for me. As far as I know, new trailing arm castings are not available so we are left with rather tired, 25+ year old units & these were never designed to handle the sort of power/torque you intend, far more than a even racing "6'" would put down. What about incorporating modified Jag stuff which seems to be the choice of most of the custom guys? Quote Link to post Share on other sites
robgeev Posted March 8, 2004 Report Share Posted March 8, 2004 Considering my engine in road going trim will be putting out 380 - 400 hp at the flywheel when installed, do people think that the following mods will be enough: Salisbury Ltd slip diff, Modified Cosworth steel driveshafts and steel Cosworth Hubs. Helicoiled trailing arms, Trailing arms machined and fitted with Roller Bearings. Vertical Shock conversion (The TR Bitz one is already on the chassis?) and Anti roll bar , not sure which yet. Bloody hell! This must be quite a motor! I agree with other post, will probably disconnect from chassis before breaking diff/shafts. I have limited experience with Salisbury diff's in military Land Rover applications, even without modification they can take tuned v8 power, so in my opinion, leave well enough alone, think staying Polybush would be best, a little flexibility is a good thing, I think. Rob. Quote Link to post Share on other sites
Guest Neil Russell Posted March 8, 2004 Report Share Posted March 8, 2004 The other option is to build with a definite weak link in the chain and drive with a delicate right foot? My feelings are that a road car will not nearly stress the rear end in the same way as a racing car. I am guessing that the race cars are putting out some 250hp at the flywheel and obviously a TVR motor will be a significant increase. I on the other hand won't be doing drag strip starts. Presumably the racing guys are still using std componants and if so we know that they are good for 250hp? How common are the failures? I have a lot of good kit already on the chassis, so if the salsbury LTD Slip diff, cosworth hubs and driveshafts can stand up to it then in theory the only thing left would be to fabricate some replacement trailing arms in steel. Presumably these cannot be that bad a problem though? my reasoning is that lots of IRS cars are on the road and if they were breaking frequently then we would all be searching for replacement second hand parts or clammering to have new ones re-manufactured. I think that my starter is to fit the best of what is available and see what breaks? Neil. Quote Link to post Share on other sites
Richard Crawley Posted March 8, 2004 Report Share Posted March 8, 2004 and drive with a delicate right foot? I, on the other hand, won't be doing drag strip starts. Oh yea; probably not in the first week anyway! Quote Link to post Share on other sites
jonlar Posted March 8, 2004 Report Share Posted March 8, 2004 What's the point of building a car with much power and then not using it - it's like these bods that win a million or the Lottery and then say it's not going to change their lives - What a Waste!!!??? Quote Link to post Share on other sites
Guest Neil Russell Posted March 8, 2004 Report Share Posted March 8, 2004 Who said I wont be using it? i just said I wasn't going to use it all Quote Link to post Share on other sites
Andy Moltu Posted March 8, 2004 Report Share Posted March 8, 2004 I have heard that some of the racing 6's are putting 250 bhp+ at the rear wheels so the flywheel output may be considerably more than that. Quote Link to post Share on other sites
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