The adventures of dyno dog pinto

[Graham]

I guess a follow on question I have for you, do you think you concluded that the 40DFI is too big for the pinto or too big for the standard manifold? I can’t get my head around it being too big for the engine when people use twin 44 IDFs, 48 DCOE’s etc?

Cheers

twin carbs are using individual runner set ups with one choke per cylinder, thats a totally different ball game to a common plenum manifold.

i concluded the DF15 was too big for a couple of reasons, the massive main jets it needed was the first clue, the second being it gave so little more than the 32/36.

As it picked up some midrange torque but only 1bhp at the top end i believe the manifold was holding the engine back not the carb

[Sidways93]

Ok thanks, that makes sense. Just looking at your previous posts to others should I try F2 and F3?

If it is F11 then try a F3.
Same tube wrt the holes as an F11 but it has a thinner tube which means there can be more fuel in the well (proper word?) where the tube sits in.

[Miniliteman]

Yes you could try both. F3 is a smaller F11, F2 is a smaller F15. Difference is F2/F11 has 4 more holes at the bottom of the tube. Smaller tube for a / one carb on a normal manifold that normally feeds one independant runner.

[Dyno]

I told you years ago, you need at least 170 Bhp to see any advance, usual a few horses. Tried all the same, bigger is not always better

This was replay on the exhaust manifold but the quote did not came with my answer

[Group4_Mark2]

Excellent thread. Very enjoyable read and great videos to go with it. Thanks

[Graham]

I told you years ago, you need at least 170 Bhp to see any advance, usual a few horses.

yes you did, but that doesnt make for a good test for a magazine!

[Dyno]

Would love to read whole topic here but I don't have any spare time anymore to follow up TS (sad to be honest).

Maybe I catch up later.

Is this all for a magazine, test work to be written down?

[Graham]

Is this all for a magazine, test work to be written down?

some of it, some of it is for my you tube channel, and some of it for clients and some just for fun

[Dyno]

ok, nice

[Sidways93]

Yes you could try both. F3 is a smaller F11, F2 is a smaller F15. Difference is F2/F11 has 4 more holes at the bottom of the tube. Smaller tube for a / one carb on a normal manifold that normally feeds one independant runner.

Tried F3 but not significantly different I’m afraid, think using a compact design carb usually for independent runners is just asking slightly too much from it. Still performs relatively well just can’t get the most from it.

[Sidways93]

Graham,

Do you have any views on one twin choke manifold being better than the other, I see some have a number starting 71 and some 82. Thought I read there was a better one to start with but can’t remember where I saw that now.

Cheers

[Forest_rallying]

Graham,

Do you have any views on one twin choke manifold being better than the other, I see some have a number starting 71 and some 82. Thought I read there was a better one to start with but can’t remember where I saw that now.

Cheers

The HT1e has over 5mm of overlap @ TDC, totally unsuitable for the carb and manifold you're trying to use.

I have a GTS4 cam in an engine on 45's with 36mm chokes and there's bugger all power and torque until well over 4000 Rpm.

[Sidways93]

The HT1e has over 5mm of overlap @ TDC, totally unsuitable for the carb and manifold you're trying to use.

I have a GTS4 cam in an engine on 45's with 36mm chokes and there's bugger all power and torque until well over 4000 Rpm.

Yea I understand It will be a compromise, only really solved by changing the cam or going to splits - neither of which I want to do.

I don't run my IDF on a standard pinto manifold btw and it certainly isn't as poorly behaved as the engine you mention above, it's actually pretty drivable and responsive low down. Not amazing but it is competition engine after all.

Cheers

[Forest_rallying]

Yea I understand It will be a compromise, only really solved by changing the cam or going to splits - neither of which I want to do.

I don't run my IDF on a standard pinto manifold btw and it certainly isn't as poorly behaved as the engine you mention above, it's actually pretty drivable and responsive low down. Not amazing but it is competition engine after all.

Cheers

I hear what you're saying Sid defending the cam but in my eyes the HT cams are Race cams, that's the nature of HT's business, not Rally engines.

Have you had your engine on the Rollers yet to see where the power band starts? A lot of competitors are prepared to sacrifice 15 bhp mid range to get 5 more at the top end. See one of Grahams graphs of the F2 Stock Car cam and you'll see a massive dip in the power until it comes on cam.

My experience of Road Rallies goes back well over 40 years, running a variety of Lotus Twinks of various capacities and cams including L1's. We then moved onto Pintos of various specs trying different cam and carb set ups. Our final RR engine was one with a BF 63 cam and split 48's for the 1997 season which included MN events. That engine pulled hard from 2.500 rpm right through to 8K. In my opinion it was a better engine than the NA Cosworths that we campaigned in the 90's on Stage events.

There's some interesting reading somewhere on this Forum if you can find it on RR engines including the Gentleman commenting from Mossley's Dyno in Wales. A fascinating read to hear different peoples opinions of the old Pinto engine.

I wish you luck with your quest.

[Sidways93]

Yea I’ve read the old threads, do make interesting reading as does this one. Yea my car has been on rollers a few times. Would put my graph up if I could remember how.

Thanks

I hear what you're saying Sid defending the cam but in my eyes the HT cams are Race cams, that's the nature of HT's business, not Rally engines.

Have you had your engine on the Rollers yet to see where the power band starts? A lot of competitors are prepared to sacrifice 15 bhp mid range to get 5 more at the top end. See one of Grahams graphs of the F2 Stock Car cam and you'll see a massive dip in the power until it comes on cam.

My experience of Road Rallies goes back well over 40 years, running a variety of Lotus Twinks of various capacities and cams including L1's. We then moved onto Pintos of various specs trying different cam and carb set ups. Our final RR engine was one with a BF 63 cam and split 48's for the 1997 season which included MN events. That engine pulled hard from 2.500 rpm right through to 8K. In my opinion it was a better engine than the NA Cosworths that we campaigned in the 90's on Stage events.

There's some interesting reading somewhere on this Forum if you can find it on RR engines including the Gentleman commenting from Mossley's Dyno in Wales. A fascinating read to hear different peoples opinions of the old Pinto engine.

I wish you luck with your quest.

[Graham]

no perhaps the most interesting test, but here is a test from a 32/36, pair of 40's and 45's all on the the same bog standard head/dyno dog

https://youtu.be/5Bt40oDpouo

[katana]

You didn't mention what chokes were in the 40's - i'd assume 34's like the 45's? If so, then the power improvement is clearly (maybe) down to bigger potential air volume squeezing through a similar hole, speeds up, pressure down allowing better fuel pick up? Just a theory!

[Graham]

You didn't mention what chokes were in the 40's - i'd assume 34's like the 45's? If so, then the power improvement is clearly (maybe) down to bigger potential air volume squeezing through a similar hole, speeds up, pressure down allowing better fuel pick up? Just a theory!

40's had 32 chokes, bigger gives no gain as the aux vents and throttle restrict airflow more than a 33 choke, so all you end up doing is fitting bigger mains

[Graham]

ok next instalment, Dog gets a big valve head, p4

https://youtu.be/jDQFVbEPHGs

[Sidways93]

ok next instalment, Dog gets a big valve head, p4

https://youtu.be/jDQFVbEPHGs

Interesting vid. That cam seems pretty impressive to me!

[Miniliteman]

ok next instalment, Dog gets a big valve head, p4

https://youtu.be/jDQFVbEPHGs

Graham, on the dyno-run (at 2:37) the engine sounds very rough, like the carbs are not synced properly. Or is it just me?

[Graham]

Graham, on the dyno-run (at 2:37) the engine sounds very rough, like the carbs are not synced properly. Or is it just me?

possibly, if im just power testing i dont put a lot of effort into getting the carbs bang on right at the bottom end/part throttle as it has no effect WOT

[Enea]

Super interested in the manifolds test, as I'm going to make that choice next winter, my engine spec look quite similar to that of dyno dog, power should be similar too, and now I'm using the standard ashley manifold which I think should be robbing a good bit of power up top.

[Graham]

I'm using the standard ashley manifold which I think should be robbing a good bit of power up top.

i'll tell you now it isnt!

[Graham]

Graham,

Do you have any views on one twin choke manifold being better than the other, I see some have a number starting 71 and some 82. Thought I read there was a better one to start with but can’t remember where I saw that now.

Cheers

TBH ive never noticed any difference, and from the small gains ive seen by modifying manifolds i dont think there would be much difference anyway

[Enea]

i'll tell you now it isnt!

My spec is 44idf (34chokes), kent fr33, gp1 valves, 11.3cr with forged rods/pistons, cnc heads stg3 head.

Depending on the rollers graph, I'll probably switch to something with a bit more lift, like rl31.

It's a gravel rally car, so torque between 3 and 5k is key.

I think I'm having it custom made here from stainless steel, as I don't think it will be much more expensive than have a full set shipped from uk, hence the interest in having 1.5 or 1.75 primaries.

[Graham]

I did a test for classic ford magazine, 3 different 4,2,1 manifolds on a 152bhp engine, the small bore 4,2,1 was best, the big bore 3 piece lost a ton of torque everywhere, and a mega expensive 5 piece big bore long primary manifold didnt give any real benefit either, that test is coming in a video soon.

ive since repeated the test on a more powerful engine, results are pretty much the same.

You do NOT want 1.75 inch primaries

[onecamohv]

What's the OD of the small bore primaries Graham, 38 mm?

[Graham]

What's the OD of the small bore primaries Graham, 38 mm?

from memory yes

[Enea]

What i'm not convinced about in the Ashley STD manifold Is the lenght of the primaries, it's about 30cm, which Is way too short in comparison with every formula I found to calcolate It. So ideally I would Need 1.5in with longer primaries, around 60/70cm, with the Classic shape of the Simpson and srd manifold.

[Graham]

What i'm not convinced about in the Ashley STD manifold Is the lenght of the primaries, it's about 30cm, which Is way too short in comparison with every formula I found to calcolate It. So ideally I would Need 1.5in with longer primaries, around 60/70cm, with the Classic shape of the Simpson and srd manifold.

personally dont put too much store in formula, there are always unaccounted for variables, better to test and see what works. from testing i would say on engines upto 175bhp the SRD manifold works better than the 3 piece ashley type manifold, but the small bore is still better

[onecamohv]

What i'm not convinced about in the Ashley STD manifold Is the lenght of the primaries, it's about 30cm, which Is way too short in comparison with every formula I found to calcolate It. So ideally I would Need 1.5in with longer primaries, around 60/70cm, with the Classic shape of the Simpson and srd manifold.

id agree, id be shocked if the small bore Ashley wouldnt improve further with much longer primaries, id imagine to see an earlier and flatter torque curve

[Enea]

What I don't really understand, why doesn't the exhaust companies produce the small bore exhaust in stainless and with the bigger bore layout?

Are they only looking to 200+ hp engines? Where the bigger bore is the optimal choice?
Because I guess they do they own research and dyno testing.

Anyway thanks for the imput, Now I only have to see how much it wil cost to have it custom made, I imagine it's not cheap

[Graham]

What I don't really understand, why doesn't the exhaust companies produce the small bore exhaust in stainless and with the bigger bore layout?
:

its a common theme, customers are magpies they think bigger is better, given the choice most wouldn't buy small bore because bigger will be better. Development is expensive, at the end of the day exhaust manufacturers are not looking to supply the best of all eventualities, they just want to make as few exhaust types as possible and as much money as possible.

[onecamohv]

its a common theme, customers are magpies they think bigger is better, given the choice most wouldn't buy small bore because bigger will be better. Development is expensive, at the end of the day exhaust manufacturers are not looking to supply the best of all eventualities, they just want to make as few exhaust types as possible and as much money as possible.

exactly, run off the mill budget companies like Ashley, sportex, etc i bet have never done even 1 dyno session on their products. they are built to a budget for the masses to a size that 'sells' not a size that performs at that price point.

I built a stainless manifold for a historic FF2000 few years ago, and the customer insisted on 45mm. i managed to pound him down to 42 after many an argument, not the 38mm i wanted.
i made the primaries as long as i possibly could. the car still performed really well, but i think it would have pulled out of certain corners better with 38mm primaries.
there was a 45mm primary on the car when it arrived, and i said if it didnt perform better on the rollers, come back. never heard from him again

[Forest_rallying]

The two Davids, Vizard and Baker, not Owen and Steele both said that the small bore manifold with a 2 inch system was adequate for the best part of 200 bhp which as we all know most Pintos aren't. I think there was a Dyno test somewhere that I read many Moons ago and this confirmed what they were preaching. Most exhaust fabricators manifolds have never seen a dyno for development, they work on the theory that bigger's better especially when the bonnet's lifted.

We had a Big 4 into 1 up and over manifold on a 2.3 NA Cosworth as I have said many times. The manufacturer made exhausts for some of the Works Teams including Vauxhall so you would think they would know a thing or two. The workmanship was second to none, all the welds were oxyacetelene and done to a very high standard. The primaries were over 2 inch in diameter which was far to large for that type of engine and we always struggled to get any low down and mid range power out of the engine. We eventually had to admit defeat and try a smaller 4/2/1 manifold which worked a treat. You could hardly see the manifold under the bonnet after looking at the big up and over but it didn't mater because the engine performed so much better and the car was at last a pleasure to drive.

[mexicotait]

in very un scientific terms i have just done similar i had a far too large 4-1 crossflow manifold only ever had it on because i was given it i have just chaned to a cheap and cheerful sportex 2inch outlet and what a difference

no other changes the cars low down power is much better and even seems to rev better.

Plus its lighter and takes up less room in the engine bay

[katana]

Just saw the latest 36 vs 38 choke, dyno shoot-out - my god! The fuel standoff was staggering, fuel leaking out of every orifice it seemed LOL!

[Dyno]

Most exhaust fabricators manifolds have never seen a dyno for development.

That's not 100% correct. There is a different story behind it. After I found better working diameters I did contact a company in UK (well known) and told him about my sizes. He said he was willing to build a manifold for my with these numbers (and he also did) but would never take it into production. He told me, if I could bent a tube even bigger as we already do right now I would start producing them instantly. He told me it would be the best selling manifold from now on. They seemed to know very well they where to large BUT customers want big manifolds !!!!! And they want to sell, not watching others selling.

Whole different story. And believe me, what Graham discovered I already did long time ago and not only for Pinto's. I'm glad people are willing to believe Graham. Time after time I start telling something not in line with the general Internet tuning, I get rubbish over my head.

[Graham]

Just saw the latest 36 vs 38 choke, dyno shoot-out - my god! The fuel standoff was staggering, fuel leaking out of every orifice it seemed LOL!

yes a lot of fuel stand off, but then what do you expect? big-ish carbs, hot cam, big chokes and full throttle down at 3,000 rpm, once its on song the fuels only going one way.