in this video we look at a ford pinto with a GTS3 cam, split 48 webers, and retune it to make it more user friendly by fitted smaller carb chokes and a Bestek distributor
Hi, great video, thank you for that. It seems like the customer has an engine spec sheet for a high ish top end power and would benefit changing the hardware for low down torque. Interesting to see the next video, you let the viewers into depth with tuning theory. Ive learned a lot watching this channel
thanks, what i dont know is if the engine was origonally built spec'd to the customers requirements, or something else and is being adapted to do what he wants. i suspect he was advised on parts by people that didnt really listen when he said where in the rev range he really wanted it to work, When he first phoned and said it had been suggested by others he swap the GTS3 for a 4.75 or RL31, my reaction was thats wasnt going to anywhere near enough to get the power as low down in the rev range as he wanted.
Like a milder cam, smaller chokes, hopefully the exhaust ports haven't been opened right out and then it's a better starting point for mid range? I hope the customer gives you a bit of freedom to build the engine to suit his needs. Brilliant stuff you do though, you know your way round old school tuning theory for sure. Thanks for the vids
Graham, i wondered, why a split dcoe setup anyway? If you had a single 48 DCOE or may different resluting with a IDF carb, would that be more of a chance to get this lower revolution range dip out? And then yes, you may be better of with twin choke carb's. I have seen it that to many out there, thinking the bigger is better. But it is the whole package of making good power at broadest range. I did a set of carb's for an oval racer a while ago. To large carbs on 1300CC sprint class. 45 DCOE had 38 mm chokes!! I got down to 36, did the whole service on this DCOE, because all was was off the pace. It became a new different car. Made some 4 places better in the heats. So good setup engine . Torque is very well important, not just top-end... But the benchracers know it all 😄
Unfortunatly no one asked me what to fit to this engine, i would of gone with a smaller exhaust, different carb sand less compression but thats in the next video! I wouldnt of suggested splits for this set up, or at least would of strongly pushed for using 45's. At high rpm splits are way better than a single. From what ive seen a big single does make good low end torque, but falls off a cliff at high rpm and suffers fueling issues at various different points in the rev range. In my experience a single isnt much better than a DGAV/DGAS
@@PenguinMotors right about the DGAV/DGAS to a DCOE or DHLA type down or sidedraft. Just for the case needed choke size you may go swich to a single side or downdraft with 45( DCOE/44 ( IDF) barrel. Correct me if i am wrong. I do not know the GTS-3 cam. profile
Tbh I don’t think there would be much difference between ike and brooks, if the engine had been one of my dyno mules I probably would have but it wasn’t my engine so it wasn’t possible
Road rally regs is why its on splits, single dcoe has its own problems and doesnt work that well, splits work much better at the top. ultimately smaller splits are probably the way to go, but when the customer already has brand new carbs changing them isnt an option
Wonder if the richness and power drop at 3300 was caused by a bit of fuel pooling. Maybe some fuel droping out from being held at low rpm before the run. I'd have been tempted to run the power curve the other way, start at high speed and lug the engine down, see if that changed the result.
You’re correct that can/ does happen to some extent, but the dip is the same at whatever rpm you start out, however quickly you load/release it. Running the test backwards isn’t an option Niether would it be a good idea starting out at max load/rpm incase something is off. At the end of the day you don’t normally get such a big dip if you’re not running carbs too big
🤣 I have zero experience with carbs. Loving the channel BTW, only found it the other week. I remember chatting with you about flowbenches on the turbosport forum about 20 years ago.
Hello. The first and second cylinders are on the first throttle, and the second and third are on the second? Wouldn't the first and fourth be correct on one side and the second and third on the other?
Thats what a lynx cross over manifold does, but they cause more problems than they solve, This set up works, in fact its the same as almost all twin su setups, and can make really good power, but asking it to work well at low rpm is a problem, i dare say it would of been quite a bit better if the carbs had been 45's not 48's.
i would say its too big, smaller primaries would probably increase scavange and allow a reduction in main jet size which would probably help out in the dip
I didnt build the engine so i dont know what the thinking behind the build was, my task was just to try and turn it into what the customer actually wanted, in part 2 the cam will be swapped for a GTS1, i would of probably gone down to an FR30
