Atc 88 dyno results look!

[MIK6]

I have a few bigbore 70s. I have a few stock, a built all honda 88cc w manual clutch (built by jensen), a 110cc auto clutch and a 125 lifian manual. the 88 will crush the 110 in a straight line w/ same tires and gearing. It runs rite w/ my stock 125 motor set up the same way. I think the 88 has alot more torque and is snappy compaired to the 125, the 125 just pulls more due to displacement. ill have them both at TF12, anyone is welcome to try them!!

MIK6 / Mike

[81Rmachine]

That's why I ran the ol' z50 and posted results of that as you can see it read an accurate 3.5 hp for the 50. Some of my buddies actually ran their drag cars on this dyno in a 1/4 mile run and went down to Brainerd the next weekend with similar weather and were only two tenths of a second off. My friend also ran his 68 Camaro with a 496 BBC Merlin block Merlin heads, Merlin intake, a full roller cam and he made 410 HP at the wheels and he runs 10s in the quarter. My point being this dyno reads on the conservative side and Mustang is definitely one of the most accurate. Again mods weren't just simple bolt ons like most guys do. I had to do quite a bit of porting on the head and ill admit its a very peaky engine it likes to rev, definitely not a grunter. Before I machined and ported the head I had the 88 kit installed as well as the pipe and I was very dissapointed. My little 50cc honda express would walk away from it. I dont blame you for being skeptical I would be too, but if I can go from getting beat by a scooter to walking away from my brothers 200x I think the lil 88 is doin pretty good.

[torque]

all skepticizim aside if you had a vid of that little 88 walking all over a a healthy 200x you would make a few more believers. i personally would love to see that

[81Rmachine]

One other thing to note is the z50 wouldn't rev much past 6,000. It simply didn't have the volumetric efficiency to do it. It sat at that point for probably ten seconds on the dyno and wouldn't rev any higher so thats where I ended the test. With just the 88 kit in the 70 it was the same way also it just didnt rev much higher than that. Now if I can increase an engines RPM almost 4,000 thats really gonna raise HP. Horsepower is simply Torque X RPM divided by 5252. So lets say I didnt increase torque on the minibike and it made 3.5 ft lbs but I got it to rev to 10,200. That is 3.5 x 10,200/ 5252=6.8 HP and that is by just revving it higher. Now the ATC made about 8.25 ft. lbs. at 10,200 so thats 8.25 x 10,200/ 5252= 16.02 HP. Actual engine output is measured in torque not horsepower. Horsepower is a rate. I increased torque about 4.5 ft lbs as it was almost exactly the same power as the 50 before, but I increased RPM 4,000 so thats where horsepower really shot up. Most guys just see numbers and dont understand where they come from. RPM is a huge factor in horsepower, why do you think Formula one is always trying to spin their engines faster. Sure their engines make good HP but they dont make much more torque than alot of street cars simply because their HP numbers come from RPM. F1 cars will never compete with Pro Stock torque numbers, a pro stock engine may make 2000 HP but they also have about 1300 ft lbs of torque and run much less RPM. Just my lesson on HP and torque I guess when you break it down and look at the whole picture its not that hard to believe.

[81Rmachine]

http://www.youtube.com/watch?v=wBFl75yZBQ0
No race footage yet but heres just a little bit of riding around the yard on it. Its still a very mild engine at low RPM but really comes to life as it revs. Stock gearing the GPS says 48 MPH.

[briano]

Nice helmet

[KASEY]

don't need a dyno to tell me that is no where near 16 hp!!!! just from the first 20 seconds of that video.... sorry it sounds good but i am sure your not even close ,,,,,,

[81Rmachine]

Well then lets see some of your own dyno results and some footage of just how fast your 70s are Id sure love to see it!!!

[JasonB]

Regardless of hp ratings on that thing, nice work. I like it, I would rock it

[KASEY]

well i don't do dyno's but i do know i little about 70's,,, i have built a few ,,, lets see if i can find a pict or two,,, oh by the way these are all my 70 's... and i have alot more,,,,,,, so hmmmm yep i do know 70's... and i still stand on my statement,,,

[KASEY]

[AirManCam]

That is quite an output. I have built a few race engines for cars and to get more than 120hp per litre out of a two-valve engine is very good indeed. To get 180hp per litre - well, I have only come across that on four-valve full race Cosworth engines hitting around 10 or 11,000 rpm. If you are running on alcohol then that would be the reason, but if it’s on gas then it is truly amazing. The Honda Blackbird got about 160hp at best, and that was 1100cc so equals 145hp per litre. F1 engines have reportedly got around 250 hp per litre but that is using an ultra short stroke and 19,000 rpm.

Five angle valve seats, well-ported head, 11 to 1 CR, cam events optimized, these are tried and tested so what have you found?
Bill

My personal car has 200HP per liter on pump gas. We've built multiple cars that are pushing 400HP per liter. Got to love four cylinders and big turbos!

[torque]

did not think i could be aroused by 70"s guess i was wrong very nice bikes kasey

[AirManCam]

I agree, those are nice Kasey!! I'm going to build one after I finish my 350x.

[CRAZY70MAN]

Kasey....lol..... man you build some great stuff. I never chimed in when I first read this thread but coming from a guy that has raced several atc 70's that were modded.....I second Kasey's comment after that video. My 150 atc 70....inner rotor, KX head makes no where near that horse and I can tell ya if you gps'ed 48 mph you have a long way to go from where my 150 will take me. Good luck.....nice 3 wheeeler by the way. Bring it to Trikefest and you will see how fast it is.lol...sounds good