I think so too.Originally Posted by Graham
GTS5 and the 45s taking care of the strong mid range torque which is needed for the purpose and the Simpson is taking care of the upper revs.
And for faster rallies ( longer straights, more fast speed corners or even some tarmac rallies ) without the cam change ( keeping the GTS5 ) 50s with 40mm with the 3pc Ashley might work well based on the last test on yesterday’s video. That gets little complicated.
Rally use, cost aside for me its the simpson for the win, it was better than the small ashley/sportex right through the rev range, the 3 piece is only better right at the top of the rev range, which backs up what ive seen in previous tests, circuit racing id go with the 3 piece as you would be able to keep the engine above 5K
ive only got an old imperal vernier and tape measure to hand but here goes, but as as tested pipe O/D are
simpson 1.75/ 1.85/2.25 primaries 26.5" secondaries 9"
my SRD manifold is, and yes i will test it, maybe one evening next week, 1.8/2.1/2.5 primaries 26.5 secondaries 16
by way of reference the 3 piece is 1.75/2/2.25 primaries all different but roughly 13-16" secondaries 16.5
its worth noting all measurements are OD and approximate
Last edited by Graham; 01-01-2024 at 15:31.
Many thanks Graham.
It seems that the Simpson manifold is the small tube one unless they make 3 different Pinto headers nowadays.
There seems to be a significant difference between these 3 manifolds.
Wow - really short secondaries - Its almost a 4-1! The others with near double the length seem 'normal' by comparison! Must be something in it though, the way it performed!
one things for sure the engine didnt like the huge SRD manifold i started out @198 bhp on it and that was the best i got.
i only make it worse after that trying to find more power, even did a compression test to check we werent down on compression, which we werent. i just dont think we have enough engine, cam or compression to make it work.
it still could be the valve springs getting tired having some effect, if its running into valve bounce over 7500, at some point that wil also take the power off before the crital "bounce/revlimiter" point is reached, but that cant account for the fact its well down on power against the other two manifolds over a good chunk of teh rev range. . the i dont know what the springs are but they are only singles and most of the cams ive been running specify doubles or double if possible. the engine will missfire if i try running past 7500, but it didnt when i first put the burton head on it.
so im afraid, thats it im offically done with testing stuff for now.
ive got that many tests on the dyno mule it really needs to come apart for a check over, although the compression pressures are still there, it is breathing a bit. In terms of run time its now done about the equiviant of five 24hr races!
Of course the FB mob all want me to start testing FR30/32/33 etc but thats going to have to wait.
Last edited by Graham; 02-01-2024 at 23:13.
Hi Graham will you be upgrading the singles to double valve springs for future testing cheers mario.
probably, but for the moment nothings going to happen i have a back log of other stuff to do, and the engine engine needs a strip down and inspection as the engine is starting to breathe a bit and oil pressure isnt what it was
In the Kent Cams catalogue it says for the GTS7 cam that valve spring life may be reduced and to life the springs, seeing as the the GTS4 cam has similar lift that could be possible with this cam too. On the other hand it could be the head supplier just using cheap and nasty Biro springs to close the valves, maybe like the single ones another came manufacturer sells.
I think that you have proved now that you have reached the maximum power and torque that engine will produce, maybe with a slight increase in compression a little more could be found but I guess once the heads skimmed that’s it, there’s no going back. I see little point in you testing fast road cams in an engine of that specification with what has basically has a full Race head, I doubt many Road car drivers will want to go to that expense with a Pinto.
I would just like to thank you very much once again for bringing all these tests to us and sharing the information with us, no other engine builder has ever done anything like this in Public. Good luck with the Harris Pinto rebuild and getting it Dynoed, I’ll look forward to it, all the Best.
Graham,
if you look at the above graphs you see that in the top graphs the line for the GTS3 is well below that for the GTS4.
But in the bottom graph the line for the GTS3 is higher than it was in the other graphs.
Any idea why?
Hmm, obviously different scales have an effect, dunno i thats what your seeing
if i do fast road cams i will do it in a basically stock engine, i have two other dyno mules the OG dyno dog, and scrapyard dog which i think is pretty standard but has an injection head, that made 104bhp 32/36, stock cam and cast iron cortina exhaust manifold, I ran that close to destruction as its now a little low on oil pressure so i need to open that up too
Something I’d be interested to see when/if the time comes. Would still like to perk up my std pinto with a ported head and fr30 with 32/36 possibly later in the year
Got an FR30 in my engine with a mild Vulcan head and it works really well for a road engine.
Plus I live in Wales, so need something that will basically tick over nice in the 20mph limit roads
Looking at the FR30 cam data, it looks ideal for your needs with the Vulcan head, one might say a tad overkill for Wales’s ridiculous 20mph limit.Got an FR30 in my engine with a mild Vulcan head and it works really well for a road engine.
Plus I live in Wales, so need something that will basically tick over nice in the 20mph limit roads
would be more realistic maybe with some form of BVH ? std ex valves, gp1 size inlets and basic porting .
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