heres a test where i ran 3 different road rally legal carb configurations
https://youtu.be/utsIUZer-GM
heres a test where i ran 3 different road rally legal carb configurations
https://youtu.be/utsIUZer-GM
I can’t believe you are waisting time and money testing Road Rally carbs Graham, you are nearly 30 years too late. The 40/41 cam was the cam that lots used in that period, but not now.Originally Posted by Graham
Having watched the video again this morning it’s interesting that the splits are losing out on so much power and torque to the twin 45’s. It’ll be nice to see how the splits perform with a better head and maybe a BF63 or RL31 cam. What the Dyno doesn’t tell you is how well the carbs would perform with the engine in the car on the Road, I think that’s where the splits will be noticeably better, the drivability should be much like a pair of 45’s if they are correctly set up.
There is a thread somewhere on this forum from many years ago that got very nasty with some not believing the Power figures of the Brookes engines on split 48’s. Rolling Road graphs were posted and even the Dyno operator commented that the engines were giving around 200 bhp at the flywheel. Back in 1987 my 2087cc Pinto with split 48 Dellortos and a BF63 cam gave 152 bhp @ the wheels. That was a quick car back then, it pulled from 2000 right through to 8000 RPM with no hesitation or flat spots whatsoever.
IkE sent me the carbs to testi wouldnt of gone out and bought a set
Not at nearly 2k for the splits.IkE sent me the carbs to test
no but it does give the operator a clue. you do get a feeling of how the set up responds to throttle, with a low load setting the engine will rev as if you are in a low gear, or if you have a high load dialed in you get a simulation of giving the engine full throttle in a high gear at low speed or steep hill. but i cant put that on a graph!
Hardly a waste of time when there are many many people still running pinto engines on road rallies and targa rallies which run to the same regulations. Camshaft may not be a current choice but the tests still give good information.
Interesting results.
I ran a 44IDF single downdraft on a Holbay manifold, it made good top end power on the rolling road and mid range when on cam it felt very responsive to drive. It wasn’t very drivable from a standing start and very low down though which I expect was partly down to the manifold design.
I then went to a single 45 Dellorto on the Mangoletsi inlet manifold (very similar to Lynx - some say better). I ran it on 36mm chockes and despite it making 10bhp less than the IDF I much preferred the way it felt on the road and pulling off from controls etc.
I think it shows that if anything by going to splits you aren’t going to gain huge power but possibly they do drive better on the road, but for the cost difference it does seem a lot to justify it. Saying that with many people chasing 200+ bhp on road rally engine splits are probably the only way to provide that much fuel and air.
Cheers
Last edited by Sidways93; 05-11-2023 at 10:42.
it wasnt part of this test, but i did previously try a single 40dcoe that was a waste of time might as well stick to a 32/36
will probably use a BF63 next time
Good work Graham what compression ratio are you going to run with the burton head cheers mario
it will be about 11.3, so same as previous head, that way any difference is down to the head alone not compression change
Last edited by Graham; 05-11-2023 at 12:11.
The Pinto engine might be popular down in the Valleys still with the RR boys but for most of the Country competitors are either using modern 16v engines in their Escorts or have even moved on to other makes and models of vehicles due to the absurd costs of an Escort for both RR and Targa events. Back in the 80’s it became known as formula RS 2000 for Road Rallies as approximately 85% of the entrants were Pinto engined Escorts.
In 1984 when the single carb ruling came in we first tried a 45 Weber on an Auto Vita manifold, it was absolutely pants, no matter how many times different Rolling Road operators tried, they couldn’t get rid of a massive mid range flat spot. The best power figure we saw was 115 bhp @ the wheels on a WR40 cam.
Last edited by Forest_rallying; 05-11-2023 at 17:04.
Graham, can you add some details like what chokes, jets, tubes and also final ignition timing?
what on here in in the videos? Im always reluctant to give out jet settings because theres so many variables, id rather someone didnt copy them and melt their engine.
From memory the single 45 had 38mm chokes which was probably plenty big enough and the splits 40mm which i think is over kill. Peak torque figures are close enough i dont think the differening choke sizes were having any real effect
Not in the videos. I understand you don't want to give details also because people might copy them without exactly knowing what they are doing.
I am one of those who’ve moved on to a modern vehicle, partly due to cost and also because I fancied a change.
I think you are underestimating how many pinto engined Escorts that are still out on the lanes, they still out number the modern engines in Escorts. Certainly in Wales where the majority of road rallies take place.
I heard horror stories of the single manifold but I jetted the carb using a website guide (Dave Andrews rings a bell) and took it to the rolling road. It was spot on made good power, no flat spots and I really liked it. I probably could’ve achieved the same with a DGAS or similar.
SU’s or Mikunis on a split manifold with something I fancied trying, I know it has been done already by some.
Cheers
Posting Permissions
Reply With Quote
Bookmarks