mikeday Posted April 20, 2015 Report Share Posted April 20, 2015 Could anyone let me know the BHP of an original TR4A engine, and what it will increase to now I am having it tuned to fast road - 89mm pistons, fast road cam etc, Thank you. Mike Quote Link to post Share on other sites
mike3md Posted April 20, 2015 Report Share Posted April 20, 2015 Mike, If you are not doing the work yourself, then the person/firm should be able to advise on the expected output for the mods you are having. Otherwise there are few on here who can suggest what you might get, if you can supply details of which cam/exhaust/head/valve mods you are contemplating? Original spec basic info here, on the TR Register website: http://www.tr-register.co.uk/tr4.php Mike Quote Link to post Share on other sites
mikeday Posted April 23, 2015 Author Report Share Posted April 23, 2015 Thanks for that. According to Rees Bros. who are doing the work, the BHP will go up by about 7%. So - 107 bhp.... Mike Quote Link to post Share on other sites
RogerH Posted April 23, 2015 Report Share Posted April 23, 2015 Hi Mike, I think the TR4A engine pushed out apprx 114BHP. Increasing the bore will do a number of things - increase compression ratio a touch, allow more air (and thus fuel) into the pot. The cam will allow more air/fuel in again. And then you have the exhaust and polishing of bits and pieces. I would have 7% was meagre- I'm sure I've seen 130+BHP Have you spoken to a proper engine shop. Roger Quote Link to post Share on other sites
TR 2100 Posted April 23, 2015 Report Share Posted April 23, 2015 +7% is ridiculously low. Way more than that. First reaction was to question the knowledge/expertise of the garage, but perhaps some sort of misunderstanding? It's not just the outright power - 89mm pistons/liners will give far more torque. 130ish would be a reasonable expectation - at the flywheel, not at the rear wheels. AlanR Quote Link to post Share on other sites
Alec Pringle Posted April 23, 2015 Report Share Posted April 23, 2015 Original quoted output for the TR4A 2138cc was 104bhp, but a more realistic expectation with ancillaries and standard exhaust fitted, as per modern measurement, might be nearer 90-95bhp. Just how much extra power can be achieved by fitting 89mm pistons and a 'fast road' cam will depend on the cylinder head configuration, the distributor configuration, just how well the engine is built, and the exhaust system. Infinitely variable equations . . . . . . I've seen engines built with nominally identical paper specifications, but actual power achieved on a proper engine dynamometer anything between 110 and 130bhp. If Rees Bros are saying 7% increment, that presumably indicates that they know their own level of expertise ? Cheers Alec Quote Link to post Share on other sites
Ernest Posted April 23, 2015 Report Share Posted April 23, 2015 Hi I see some comments on this thread related to Rees Bros. I would just like to speak up for them. Having recently bought a TR4A I took it to Rees Bros two weeks ago for a free check-over re. condition - Andrew Child carried out the check and I did feel that he was very thorough and I was very impressed with the workshop as well as with Andrew and with a another member of staff that I got into TR conversation with. Post the check-over (which was very positive re. the car) I sat with Andrew in his office and went through possible, and cost effective, ways of improving performance. I have had some experience of TRs (and most 60s/70 British sport cars) over the years so do have some understanding re. performance mods. I came away from Rees bros. impressed with Andrew's suggested levels of improving performance and felt confident about using them if/when I do decide to progress to some work on the car. I would say that I have no other connection to Rees Bros. than this one visit. I know that we can have different experiences of garages but, I the context of this thread I felt it might be useful to offer my own experience of this garage. I am thinking that the suggestion made earlier on this thread of a possible misunderstanding migt be correct. Ernest Quote Link to post Share on other sites
Alec Pringle Posted April 23, 2015 Report Share Posted April 23, 2015 Misunderstanding there may well be - as in 7% of what, exactly ? Rees Bros have been around a long time, and I wouldn't be expecting them to exaggerate the possible gains from modifications . . . . . there are plenty of other specialists around with a propensity to inject a generous dollop of optimism into the equation !! 'Fast road cam' can imply any one of several possible specifications, most of which will require significant attention to ignition, head, induction, exhaust, then there's balancing - time is money, all too often the owner does not appreciate just how much additional time/effort and therefore money is required to make the most of go-faster goodies. If all that's involved is bigger pistons and a change of cam, 7% increment above 'standard' probably is realistic. Cheers Alec Quote Link to post Share on other sites
Chilliman Posted April 23, 2015 Report Share Posted April 23, 2015 (edited) Mike, the whole issue of improving/upgrading engines is a massive subject which is oft debated, as has been said above by Alec there are many upgrades that can be made but they need to be considered in context with each other and most of all what you want to achieve I.e. what are you going to use the car for? & what are you expecting from it? Once you've established that you can make sensible and proportionate changes with those particular objectives in mind but remember each and every change you make will have an impact on some other part of the car be-it drive train, braking or suspension. I have no intention of commenting on the ability of your chosen engine builders but 7% on a stock engine is not very much to look forward to if you're making significant and costly changes, earlier this year I finished building a four pot which I used at the track day at Castle Combe the other week and it is blisteringly quicker than the previous engine, on the rolling road it's showing 142.7 but that is as part of a fully considered package of alterations and I believe that is small fry compared to some of the engines used by other forum members for racing and rallying. The world is your oyster........ Edited April 23, 2015 by Chilliman Quote Link to post Share on other sites
Andrew Smith Posted April 23, 2015 Report Share Posted April 23, 2015 Rees Bros: engine upgrades - ask one question: do they do the engine work themselves.................. Cheers Andrew Quote Link to post Share on other sites
stuart Posted April 23, 2015 Report Share Posted April 23, 2015 Mike you have PM. Stuart. Quote Link to post Share on other sites
monty Posted April 24, 2015 Report Share Posted April 24, 2015 Mike, the whole issue of improving/upgrading engines is a massive subject which is oft debated, as has been said above by Alec there are many upgrades that can be made but they need to be considered in context with each other and most of all what you want to achieve I.e. what are you going to use the car for? & what are you expecting from it? Once you've established that you can make sensible and proportionate changes with those particular objectives in mind but remember each and every change you make will have an impact on some other part of the car be-it drive train, braking or suspension. I have no intention of commenting on the ability of your chosen engine builders but 7% on a stock engine is not very much to look forward to if you're making significant and costly changes, earlier this year I finished building a four pot which I used at the track day at Castle Combe the other week and it is blisteringly quicker than the previous engine, on the rolling road it's showing 142.7 but that is as part of a fully considered package of alterations and I believe that is small fry compared to some of the engines used by other forum members for racing and rallying. The world is your oyster........ Is that 142.7 @ the flywheel or @ the wheels? Seems to be very high if @ the wheels if you assume the usual loss difference of around say 25 to 30 between flywheel & wheels. Cheers. Quote Link to post Share on other sites
Chilliman Posted April 24, 2015 Report Share Posted April 24, 2015 Is that 142.7 @ the flywheel or @ the wheels? Seems to be very high if @ the wheels if you assume the usual loss difference of around say 25 to 30 between flywheel & wheels That's at the flywheel which from memory was barely just over 100 at the wheels, someone may prove me wrong but I don't think it would be possible to produce that kind of power at the wheels with a four pot. Quote Link to post Share on other sites
monty Posted April 24, 2015 Report Share Posted April 24, 2015 That's at the flywheel which from memory was barely just over 100 at the wheels, someone may prove me wrong but I don't think it would be possible to produce that kind of power at the wheels with a four pot. Yes that is what I had concluded when I read your earlier posting. My 4 is giving 114 at the wheels & am assuming that to be around 140 or so the flywheel. My less tweaked 4A is around 100 @ the wheels with around 130 @ flywheel. I do have a top TR4 racer friend of mine who quoted me something somewhat higher but he is running the very max size possible in Pistons etc! All great stuff! Cheers. Quote Link to post Share on other sites
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