Gday men,

 About to do my stage 4 and the guys are telling me that the 58mm Throttlebody and bigger injectors are overkill, they say to leave the standard injectors and throttlebody on....

Guys, I need advice quick if any of you have first hand knowledge.... Ando, or Chriso????? Anybody with a stage 4, please give me advice.. 

Cheers

Rans

Hi Rans,

Im in the same boat at the moment.

If it comes in a factory kit I would try it and see how it goes thats what im doing.

If you are putting the kit together your self go for a HPI 51mm or 55mm.

In the end alot of it is in the tuning, a good tuner with make either work equally well.

Just my view any way.

Good luck. 

Thanks fellas, what about injectors though?? do I need to change them or not??

Rans

Stock injectors are good for 100hp I think.

Correct me if I'm wrong.

All depends on who is tuning, i have seen a few bike make more power in the topend after going up in size from 52mm, but this is just from a throttle body, the tuner also needs to be able to find that power. If your tuner is telling you it is a waste of time then it will be as they are not able to find more in the tune.............................and from what i have seen allot of tuners usually leave plenty left on the table when it comes to harley efi tuning.

T1

I have the kit fitted , 58mm + bigger injectors  goes great and I assume harley  did the R&D for the kit getting 110 hp 111 tq

sorry Rans only just spotted the thread mate, anyway as i said on phone mate, 58 is being used with the kit for a reason and i certainly have had no troubles nor have any of me mates. Fucken flys 110/108 and great to ride right through rev range

58mm it is then.

Did your kit come with ACR's?  Picked  mine up  yesterday and they were fitted to the heads. Bonus as I hear that they're not included.

Had to buy the harness though.

Looking at the new injectors that come in the kit and they have 3 spray holes the stock ones had about 5 or 6 I think.

Also got 4 head gaskets.  ????????

I have the 103 street stage 4 kit, with the 58 T/B, nothing wrong with it. Next time i would go the 103 pro stage 4, has another 5 TQ and 10 HP. I find the bike pulls from 2000rpm in first 3 gears, needs to be round 3000rpm in 4,5 and 6 gear to pull heard.

 Got my se 50mm from eBay new 350 +Post comes with bigger iinjectors ,

tbody ready for the big ports too

The latest Heavy Duty mag has seen Doc fit a 58mm to ugly betty and has some great figures coming from it. Nev Lush puts the tune in and got 111/112 out of it.

I personally have no experience, just repeating the latest mag.

Regards

Have a HPI 62mm t/body with 1.8" inlet runners and set of HPI 6.23gps injectors ready to fit onto the Bob, should be interesting to see how it affects the current dyno curve and numbers.

The SE 58mm TB is good. You will get MORE torque not less.More low end not less. On a stage 4 out of the shop ( read just thrown together) with a good exhaust I just got 118hp a couple of months back. That was with the E cam that come with the kit...  and a SEPST. Doc's bike came up a treat, bear in mind the heads/cam combo is bolt on and the touring exhaust is not biased to power above 5000 rpm. That bike would do more with a more aggressive exhaust. It was a fat porker or whatever stupid name they call the S&S 58 TB not the SE 58. Hope this helps as I re registered especially for that. :-)  oh BTW respectfully Russ4570 I made the tune I did not put one in.

Throttle Hog

what size build are you putting the 62 TB on carbon fibre ?

4.5"x4.125"

Russ4570 thats cool I was not thinking bad. carbon you are making a 130 cuber then or 2138cc. Maybe you need a 70mm TB ? :-)cheers

no Nev, = 120ci
but before I elaborate, great to see you back here.

Engine thread is here, twincam 120 build.

Built it just before HD released their version.
Currently runnin 640 sticks with R&R heads, HPI 55mm tbody, 5.3 injectors.11.75:1 comp
The new 62mm will be mated to an updated version of the R&R heads(2" inlet, revised ports)
not lookin for low end, Lol.
Once again, good to see knowledge back on this forum.

 4.5  x 4.125   I get 131 cubes maybe my calculator is off or your engine is bigger than you think :-)

Your off mate, 4.5" stroke, 4.125" bore is 120 all day. Lol