Harris pinto dyno test

[Graham]

Great video and info, great test as always! I’d like to see the same setup on twin 45s with 38&40mm chokes!
long & short intake manifold and different length trumpets!

there are always more tests that can be done, but there are two reasons i didnt run it on 45's, i didnt have the time, and its a customers engine, so theres a limit to how much running you want to do on someone elses engine just for fun!

if you read through teh cam test thread you will get an idea about 45's, it wouldnt of been a lot different

i can answer the manifold the intake question though, dont bother with short longer is better

[mariors2000]

Hi Graham even after all the camshaft test you have done you still used your favourite cam the rl31 both in a street car and race car but both being 2.2 litres great work .

[Graham]

Hi Graham even after all the camshaft test you have done you still used your favourite cam the rl31 both in a street car and race car but both being 2.2 litres great work .

had the engine not been on such big carbs, i might of fitted WR40 or GTS5, both of them would of made more horse power, but would of sacrificed some low end power. BF63 would of probably also been a good choice, more low end but less top. My (quiet) goal was to match the pre rebuild power and have bottom end grunt. In my 2.1 dyno mule on similar head and compression that showed 183bhp, so i figured it would just about match the old engine for power, and so it did

so i in the end i fitted the Rl31 because i knew in this case it would deliver, i was pretty certain if i fitted any other cam i would be back doing cam swaps.

i dont think the RL31 would be any good as a circuit or drag racing cam, unless for some reason you cant go past 7000rpm.

Speaking of drag racing im working on an engine for the drag strip right now, this is 2.0 and we are going to have to rev it HARD so HT1 is minimum cam im considering for that but will probably end up with something hotter

[mariors2000]

Hi Graham at what rpm range do you think it will peak at cheers mario.

[Graham]

what the drag engine? its not so much where it peaks, more that it has to start early enough to cope with the launch and hang on long enough that all the power doesnt dissappear before the end of the strip. The current drag engine is actually fitted with an RL31, but its so out of puff at the big end that the driver says it feels painfull, just hanging in there not really accerating anymore just waiting for the finish line.

i would say he probably needs a peak around 7500, but it needs to hang on to at least 8K

[mariors2000]

Hi Graham are you going to do a video on the drag pinto motor cheers mario.

[Graham]

Hi Graham are you going to do a video on the drag pinto motor cheers mario.

https://youtu.be/Iej8OOxhg90

[BROWNY]

looks like you been busy Graham, cant wait to see how this one turns out

[mariors2000]

E Hi Graham great video since head flowing around 200 cfm at 28 what hp do you think the motor will make since its is a ture 2 litre engine cheers mario.

[Graham]

E Hi Graham great video since head flowing around 200 cfm at 28 what hp do you think the motor will make since its is a ture 2 litre engine cheers mario.

dont know if its a true 2.0 or not! 2.1 is actually 2090cc and this one is 2045cc. we have enough airflow for comfortably over 200 bhp.

[BROWNY]

wow, thats a nice big number so looking forward to this one on the dyno

[onecamohv]

i usually start by retarding the cam, usually thats how you get more power, if i retard it a bit and power drops i will try advancing it, but if you retard it and gain power no point in trying to advance it, unless your purely looking fo rlow end grunt.

cranking pressure was about 190psi, so in the sensible range.

squish is a funny thing, everyone says you need loads of tight swish, but some engines have none and still work well. This engine has a little under 0.050. with really tight squish you can be in the position that the burn speed is so high you actually have to start retarding the timing. i think it pays to get tight on high rpm/race stuff.

i think with 45's carbs or ITB's longer straighter intake trumpets would of given more top end power. but this never really was about maximising power

yeah id agree with the first point in principle, but i find usually the trade off for a few BHP up top by delaying the IVC with a retarded cam is a bigger trade off pretty much everywhere else, and you mentioned its not about maximising power so i was very interested to hear the reasoning is all - Did you note any poor throttle response with it retarded? anytime i tried advancing the RL31 picked up a few bhp, mid range died and after max torque it fell off a cliff very soon after, which i ended up putting down to the engine not getting on with the later intake event.

If done right, i dont think squish is rarely if ever bad - i dont think you'll ever increase the burn speed (especially in a pinto) high enough to overcome the benefits of turbulence in the combustion chamber causing a better burn. depending on the chamber shape and area loose some power with too tight of a quench, it pale’s in comparison to the power you leave on the table by running too loose of a deck clearance, not to mention having a greater detonation sensitivity.

And regarding the backing off the ignition timing - rather than thinking that "having to start retarding the timing is a bad thing" maybe consider it this way : Tighter quench gives a higher squish velocity which means a higher turbulent flame speed, which improves throttle response and power with less timing required. Anytime you have to advance the timing for peak power, it usually indicates less efficient combustion.

Ive made a few mods to my pinto since my initial build, and its now making 203bhp, 173lb.ft with only 28 deg max advance on pump fuel (but i use NF booster for safety margin. pistons are so close to the head it blows the carbon off

Amway just Something to think about , great videos as always, keep them coming.