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Discussion Starter #41
Thanks for the info Freudie and mukle. I was grilling the dyno tech before he even got ahold of my bike. More accurately i was conversing with him to gauge his aptitude and I'm confident of his skills. After the tuning i also chatted with him about the number discrepancy between Fitzgerald #'s and he echo'd a lot of what Freudie mentioned that comparing numbers between dynamometers cant exactly be trusted but they are tools to gauge change.

The runability of the bike is much better, he was able to smooth out a few areas of the map, get rid of a IAC trouble code that kept popping up, and took fuel out to eliminate my cold start back fires which have gotten substantially worse with fall coming in New England. Specifically with timing he took out timing to smooth the power curve but also, as its been well characterized, my DTT doesn't have knock detection.

That being said, the rout home runs rite past New England Drag way and i'd have been appalled at my self i didn't take my broken in, dyno tuned, big bore bike to the Saturday test n' tune. I didn't have full leathers (Something i never had to deal with, with the 1130) so i had to keep the bike below 120MPH less i get kicked out. I was basically left with running 1/8th mile and while my RT and 60' are horrible i was pulling 7.7 at 105MPH so that bike can easily propel me past 120MPH in a full 1/4 mile and kicked off the track. Of each of the half dozen passes i made i don't even think i got up into 4th gear so theres still plenty of track and plenty of power left.

I have been toying with the idea of re-installing the Delphi and going the Power Vision/Target tune rout but really my goals are a lot more short sited; i want to get this motor running and have some fun before start modifying major components on it.

I suppose based on both your responses i have less of a worry about the raw number and can continue to have some fun not that i'd do any thing different. I am just curious.

FYI Freudie i do plan on boosting my X leaning more towards a TTS set up over a turbo, and i've got another billet Falicon 1/4 stroked crank to do it with. I dont anticipate that project taking any less time than this one did but well see.
 

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Something is wrong at FMS dyno or tuning look at the Hp & Tq figures Scott got for the hellraiser cams on otherwise stock or Stg 1 engines - if he got 170Hp 106 Tq out of a 1430 your 1487 should be equal or higher - two thoughts - 1. Are the stage 3 cams recommended with this large bore / large stroke combination ? 2. Did Scott degree in the Stg 3 cams and were they correct as delivered or did they require slotting of the cam gears ? Those Stg 3 cams are probably optimized for stock bore / engines & the farther away you get from that configuration I would think the less ideal they would be, that 1487 is pretty far out there with 4.25 + 3/8 + 2 & +1.8 valves. Retarding the timing may help but the backfire tells me you're hunch something is not correct is right on. The advance curve may need to be changed quite a bit for that engine B/S combo in addition to careful tuning so get it right now before something less than ideal happens - sounds strong but there's a lot of missing Hp there - you'll get it I'm sure - (y) :geek:
 

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170HP sounds pretty impressive from NA. With the 16psi boost that would make 350HP. Based on my own numbers I think it has to be crank power.
 

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That's a good point Mukle. I don't recall ever seeing an NA Revo with that amount of power on a dyno chart (wheel hp that is of course).

Then again, that (and several other reason) is why I never really understood why guys bore out these engines....
 

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Yea, I agree don't think that FMS N/A 1430 made 170 RWHP - It's like Ray Vreeland's way of advertising the Hp of his CP / weld up / bore kits on his website - N/A Hp it's gotta be the crank figures extrapolated from actual dyno'd RWHP figures - creative numbers fun & good to imagine & know but not directly comparable to other dyno figures unless you use the same correction numbers - I think there's another 10-15 RWHP in that 1487 to coax out but if you gave the bore, stroke, valve diameter, etc. to someone like Mike Jones or another cam designer and asked him to create a performance Stg 2 or Stg 3 cam for that engine B/S combination I'd be willing to bet it would be different than the Stg 2 cams now available or the Stg 3 Cams installed - some of the current Stg 3 design may take into account the intended use on stroked, bored, larger valve engines but it also is sold for use on stock bore/stroke 1250's so the out of the box Stg3 cam may not be ideal for this B/S combo - also it may be better to change the cam design to help take advantage of the 3/8 stroke to build more power & torque " under the curve " which is something else that gets lost in the popular single dimensional max Hp & Tq figures everyone talks about - and we get caught up in - there's a lot more to it as we all know -
 

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Discussion Starter #46
One of these days when i get back to work and can scan the dyno ill throw it on up because i think Streetrod is rite, there might be a few extra ponies as the torque peaks around 6.5K then starts to bend over. thats the reason i was thinking exhaust restriction but again I'm no expert. To be honest my original plan with this motor was to build a TTS super charged 1487 with low compression pistons, jones st2 SC cams. Scott did a good job talking me into the 1487 NA as his concern was the amount heat that, that motor build would generate and overpower the factory cooling system. as it stands that 1487 NA runs really hot theres just an envelope of heat surrounding my legs all the time. rite now in the fall its pretty nice
 

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So the question is has FMS built another similar 1487 and what were the numbers on that one - I know he probably didn't have his own dyno then but it might be comparable - obviously it runs strong with 120 in the quarter after a less than perfect launch so no slouch but maybe the exhaust cams are opening a little early promoting cold backfires but holding the scavenging back at high Rpm due to closing too soon - just a thought - so were the Stg3 cams degreed in to the standard Jones setting or just installed & checked for valve operational clearance ? What's valve bucket clearance setting .007 ? I imagine probably not much advance/retard adjustment due to Stg 3 valve to piston clearance but sometimes a little bit makes a big difference - Wish we had some adjustable cam gears we could buy like the ones they made in Australia quite a while back - Yea, so a good deep dyno session will really help you sort it out now it's broken in and see if any cam adjustment is even needed but it kinda sounds like it - ignition timing is a big factor as well get all the pieces of the puzzle working together - Good Luck dimebag & let us know - cool stuff !
 

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Discussion Starter #49
Streetrod to answer your questions:

1) The cams I went with are the Fitz Hellraiser cams not the Jones ST3 like I intended (still have the Jones ST3 though for future boredom)
The 1430 he build had the exact same set up, same piston diameter, same cams, similar clutch.
My build differed with a few slight modifications,
A fully back-cut transmission along with a straight cut second gear Via R&D Motorsports
3/8” stroke not ¼”
Falicon billet full circle crank not a weld up stock crank (Falicone is much MUCH heavier than stock)

2) Yes Scott degreed the cams and found them in spec. He does this more as a formality because in the substantial number of builds he’s done he’s stated he’s only had to alter a single motor via slotting the cam gear. from his experience the Rvo is pretty much spot on, but he checks each build just to be sure.

3) we didn’t get into the specifics and clearance checks he did but he’s a 3rd gen machinist, I’m sure he checked all his clearances before assembling.

4) again we didn’t get into the specifics on clearances but in one of the many conversations we’ve had, he’s very knowledgeable of the clearance he needed. He’s commented that the St2 harley bucket clearance is a little more lax than he’s used to he has a tighter range he builds his motors to.

5) Exhaust is an R specific D&D Fatcat 2-1 (before the all evaporated out of existence)

As far as the tune and the cold start back fire I mentioned, was definitely running rich under cold start conditions. The dyno tech said this very thing during our post tune conversation. He had to pull fuel out to get the start up dialed in as well as pulled out some ign timing to smooth out the graph.

Over all the bike ran great with the base tune Scott used to break in the motor and now that It’s been further tuned by R&R cycles it runs way smoother. little nuance things like a slight hesitation between shifting gears has been corrected and I’ve no complaints.

here’s the PDF of the run as well.
 

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Shit it can do better than that - first off the D&D although great for a stock or Stg 1 Revo engine is holding you back on a built engine - when you get back to work get a Bassani B1 1 7/8 primary, stepped 2" into the collector, a 16" muffler straight thru built especially for bored, stroked engines, ( and not so good for stock engines ) - built Revo's need to breathe and get their exhaust out into a proper diameter stepped 2-1 but if you don't want your right ear destroyed with a side exit race pipe the Bassani is the next best deal, and might actually be better. Sell the D&D, buy the Bassani, then Dyno tune it, otherwise you're wasting time and dyno $ IMHO. My 2 cents - (y):cool:
 

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There's also a correction factor for some dyno's for "running at speed" that adds about 6 - 8 % to the actual Hp figures. I don't see that mentioned on the chart but I've seen that on my dyno run before you might ask the dyno guy I can't remember which dyno it applies to and if it's the same as Mukle mentioned - crank vs Rwhp, but I think it's not that what I'm talking about is it compensates for lower than correct dyno readings due to the way the dyno absorbs and measures the Hp while the wheel is spinning and loaded - also check out Cam King's sale thread at least his Stg 3 Cams are designed for bored and stroked, larger valved engines, I would think Scott's cam numbers are similar but you might ask him just to confirm -
 

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When I refer to rwhp vs crank I mean normal physical phenomenon where is some losses in the drive path. Even transmission are floating in the oil there is still always some friction between gears and bearings which produces heat. This is called transmission and drive path effiency thus correction factor is around 10% between crank and rear wheel. This should be mentioned in the dyno chart or detail section how much losses has been added to graphs.

Measuring power in the dyno should be pretty straightforward without many correction factors. It is pure rotational physics where power is related to torque by angular speed.
 

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Discussion Starter #54
So Scott's answer to the 170 vs 141 HP is basically what every one has already stated, its machine dependent and depends on how the each tuner has configured their dyno. Scott has told me some of the parameters he uses to try and drill down, but honestly its so far over my head I'd need the guys at the shop to talk directly with him. Personally i don't think its worth it because its just a number. I built this motor to have fun at the drag strip which can be used to generate data in and of itself.

Basically my plan for the remainder of the year is to get a full set of leathers so i can go the full 1/4 mile and above 120MPH per track rules. If I'm really missing THAT much power due to something like a restricted exhaust, ripping out the baffle this winter should show some improvement times. At minimum when i data log it should show up in the fuel delivery, BLM's and measured AFR. I can do that for free before ponying up for money to swap the exhaust or ripping into the motor to swap out the hellraiser cams (keep in mind i do have a set of Jones NA Stage 3 packed away)

The bike is by no means any slouch and again its running very very well
 

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Discussion Starter #55
7/8 primary, stepped 2" into the collector, a 16" muffler straight thru built especially for bored, stroked engine
Just called D&D and the diameters on the 2-1 Fat Cat is quite comparable to the Bassai number you gave.
1 3/4" at the motor, 1 7/8" throught the head pipe stepped to 2" at the collector then stepped to 2 1/4" in the baffle

I did confirm that I have the largest baffle they make so yea, next step would be to take out the baffle and see how mad my neighbors get.

I also think this is it as far as HP an TQ numbers go, given the parts combo and the dyno shop I have access to. Again less concerned about the number because any substantial gains will show up in the 1/4 mile which is really the output I'm after.
 

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Yea, the D&D pipe is good for a stock engine Stg1, will it work on your 1487 ? yes - is it optimum with 1 3/4 head pipes and a 2 1/4 muffler ? NO. Your new engine is 32% larger than my current 1130 ! That's 32% !! - one third larger, yea, that's a lot ! Even my R had 1 7/8 primaries stock, my Bub 7 2-1 has 1 3/4 primaries ( smaller ) and no step to a 17" long 2 1/2" spiral core wide open louvered baffle to a 4" long 3" I.D. perforated resonator - so my 1130 bike picked up low end, mid range and screams at the top of the RPM range, resonator takes the ear bleed away & lowers the tone - IMHO you need at least 1 7/8 to 2" primaries, stepped to 2 1/4 " on the way to the collector then 2 1/2" entering a collector of at least 2 3/4" including the muffler - not 2 1/4 - way too small - a resonator on the back is optional to quiet it down for street use. In the interim since the head pipes and step pipes are close if I were you I would double check the 2 1/4 I.D muffler, if so pull it out and replace with a 2 1/2 or 2 3/4 perforated core baffle, ( from J&P cycles ) wrap with SS wool & re-install. That will help that big bore/stroke engine get the exhaust out, tune to that pipe combo and buy a better pipe later if you want. The smaller primaries /step you have will make your race engined bike more streetable, and help low end but will hold back max output - figure out which is more important to you and move in that direction. But let those two big jugs BREATHE ! Leathers yea, great idea, funny you legally don't need them to drag at 119 Mph but at 120 Mph you do. That's just a crazy rule everyone knows you need them at any speed you come off that bike at the track - but don't do that, even with leathers - my old chief pilot did that on an 8 second dual engine nitro Harley back in the day ( got it up on the edge of the old flat profile style rear tire ) and took out the ABC WW of Sports camera crew, spent a couple months in the hospital - not recommended. (y):cool:
 
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