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Discussion Starter #1 (Edited)
Have a '05 FLSTCI w/ 95" kit(flatop pistons),SE air,PCIIIUSB.Will be installing 37g cams,Baisley ported heads w/ 1.900x1.630 valves,RBRacing 2:1 exhaust.My question, does the stock throttlebody put out enough CFM or is it best to upgrade to 48mm or so?With .030 head gasket the comp.ratio is 9.4:1.
 

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truck95 said:
Have a '05 FLSTCI w/ 95" kit(flatop pistons),SE air,PCIIIUSB.Will be installing 37g cams,Baisley ported heads w/ 1.900x1.630 valves,RBRacing 2:1 exhaust.My question, does the stock throttlebody put out enough CFM or is it best to upgrade to 48mm or so?With .030 head gasket the comp.ratio is 9.4:1.
I have about the same build. I have a Delphi TB/intake being reworked at Dakota Kid right now. Should be on my bike next week and then on the dyno for a tune. We will know more then. Check it out here.........
http://www.dakotakidcarbs.com/WhatsNew.htm
 

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truck95 said:
Have a '05 FLSTCI w/ 95" kit(flatop pistons),SE air,PCIIIUSB.Will be installing 37g cams,Baisley ported heads w/ 1.900x1.630 valves,RBRacing 2:1 exhaust.My question, does the stock throttlebody put out enough CFM or is it best to upgrade to 48mm or so?With .030 head gasket the comp.ratio is 9.4:1.
When I did my build I called some T/B manufacturers and asked them for their opinion. It might do you well to do the same. I found this on the Daytona TwinTech website. Their comments aren't tainted by the sale of a T/B. Take it for what it's worth.

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What are the limitations of the stock throttle body?

The stock throttle body is inadequate for engines greater than 88 CID. With a 95 CID engine, the stock throttle body will not flow sufficient air above 4500 RPM. Maximum power will be limited to about 105 HP (injector flow rating may impose an even lower limit). Our tests have shown that boring out the stock throttle body is ineffective. An aftermarket throttle body greater than 50mm is required for maximum power. The stock air cleaner is grossly restrictive and must always be replaced for any performance application.

You can easily verify air flow restrictions with the TCFI Log data logging software. Examine MAP (manifold pressure) at wide open throttle. If MAP drops off as RPM increases, you know you have a problem.
 

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timberz said:
When I did my build I called some T/B manufacturers and asked them for their opinion. It might do you well to do the same. I found this on the Daytona TwinTech website. Their comments aren't tainted by the sale of a T/B. Take it for what it's worth.

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What are the limitations of the stock throttle body?

The stock throttle body is inadequate for engines greater than 88 CID. With a 95 CID engine, the stock throttle body will not flow sufficient air above 4500 RPM. Maximum power will be limited to about 105 HP (injector flow rating may impose an even lower limit). Our tests have shown that boring out the stock throttle body is ineffective. An aftermarket throttle body greater than 50mm is required for maximum power. The stock air cleaner is grossly restrictive and must always be replaced for any performance application.

You can easily verify air flow restrictions with the TCFI Log data logging software. Examine MAP (manifold pressure) at wide open throttle. If MAP drops off as RPM increases, you know you have a problem.
Very interesting! I have data logged my dyno runs and am seeing the data from the MAP sensor do exactly what they say. At 4100 rpm it goes from 101kPa and it declines continuously all the way to 6000rpm where it ends up at 90kPa. My motor guru says the same thing, it can ONLY be the TB/intake doing this loss. I talked with Andrew at Dakota Kid today, he claims that his funnel bored Delphi unit bolted up to a Branch ported head flows 196cfm. He said that under the identical setup, a Zippers 54mm TB/intake flows 193cfm. He guarantees that my MAP readings will not drop all the way through 6000rpm anymore. That's exactly what I want to solve. I'll report my results in about 10 days or so.
 

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Just to let you guys and the rest that are considering EFI builds know.....
When you go to nicely ported heads like Baisley and keep the stock TB, you are definitely holding back the flow. MAP almost always will start to drop from anywhere from 4100 to 4700 on a decent 95 and higher build with the Delphi. BUT.... the difference in HP is maybe 3 to 4 HP with a cam like the 37. And some of that may be caused by front to rear fuel reversion at high R's. So not a big deal on the TB size. Remember that you aren't hanging around in the 4000 to 5000 rpm range for very long anyway. The most that you can bore out of the stock Delphi is about 3mm MAX, and although that will move your MAP drop up a few hundred R's, it doesn't completely solve the issue you are having. Again, I'm not calling it a problem because it really isn't on a cam like the 37. This is for up to 2005 models. The 06's have their own problems in this arena, but some of those are influenced more by the smaller injector size that simply will not support high HP engines because of the limited pulse width. This, COMBINED with the TB bore, WILL cause problems on 06's that are trying to make big power.
Anyway, don't everyone go crazy buying big TB's, because in most cases you will never feel the difference. Really a nice alternative is to send them out to a guy like Dakota Kid who will not only increase the bore but also increase intake velocity due to his re-work. And that, my friends, is the real key!

As for the quote from Daytona Twintec on the inadequecy of the stock TB, while Chris Schroeder is a pretty sharp guy, his numbers on the limitations of the Delphi show that it is inadequate to maintain MAP gain. But it really does not affect streetability of most 95" builds. And his limitation on the HP number is really not a limitation at all. (BTW, you can get more that 105). MOST 95" street builds are not making too much more than 105 HP anyway. And TQ is always on the way down by the time that MAP drop occurs anyway. So what are you losing???? Not much.
Take that quote with a grain of salt!

FYI

All the best

G
 

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GRock said:
Just to let you guys and the rest that are considering EFI builds know.....
When you go to nicely ported heads like Baisley and keep the stock TB, you are definitely holding back the flow. MAP almost always will start to drop from anywhere from 4100 to 4700 on a decent 95 and higher build with the Delphi. BUT.... the difference in HP is maybe 3 to 4 HP with a cam like the 37. And some of that may be caused by front to rear fuel reversion at high R's. So not a big deal on the TB size. Remember that you aren't hanging around in the 4000 to 5000 rpm range for very long anyway. The most that you can bore out of the stock Delphi is about 3mm MAX, and although that will move your MAP drop up a few hundred R's, it doesn't completely solve the issue you are having. Again, I'm not calling it a problem because it really isn't on a cam like the 37. This is for up to 2005 models. The 06's have their own problems in this arena, but some of those are influenced more by the smaller injector size that simply will not support high HP engines because of the limited pulse width. This, COMBINED with the TB bore, WILL cause problems on 06's that are trying to make big power.
Anyway, don't everyone go crazy buying big TB's, because in most cases you will never feel the difference. Really a nice alternative is to send them out to a guy like Dakota Kid who will not only increase the bore but also increase intake velocity due to his re-work. And that, my friends, is the real key!

As for the quote from Daytona Twintec on the inadequecy of the stock TB, while Chris Schroeder is a pretty sharp guy, his numbers on the limitations of the Delphi show that it is inadequate to maintain MAP gain. But it really does not affect streetability of most 95" builds. And his limitation on the HP number is really not a limitation at all. (BTW, you can get more that 105). MOST 95" street builds are not making too much more than 105 HP anyway. And TQ is always on the way down by the time that MAP drop occurs anyway. So what are you losing???? Not much.
Take that quote with a grain of salt!

FYI

All the best

G
Thanks G,

I was starting to think about a new TB with the head work that's coming.
 

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GRock said:
Really a nice alternative is to send them out to a guy like Dakota Kid who will not only increase the bore but also increase intake velocity due to his re-work. And that, my friends, is the real key!
G
Glad to know you support their work! I spoke with Andrew at length today as he was just dropping off my reworked TB/intake at the shipper this afternoon. He was explaining how their funnel bore job vastly increases velocity of the intake charge over the stock configuration.

After looking at the 37g valve timing thoroughly, I think I'm going to reverse the 2* cam key to retard the 37 2* just for grins and giggles and see how that plays on the dyno this next time around.

Just chippin' away at it, little bit at a time.
 

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The unit in the Ebay image is a Zipper's 54mm with a manifold to fit stock length cylinders and 1.625" (stock I.D.) port diameter. Will bolt right onto a JIMS 120 or a 107" kit.
 

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Totenkopf said:
Glad to know you support their work! I spoke with Andrew at length today as he was just dropping off my reworked TB/intake at the shipper this afternoon. He was explaining how their funnel bore job vastly increases velocity of the intake charge over the stock configuration.

After looking at the 37g valve timing thoroughly, I think I'm going to reverse the 2* cam key to retard the 37 2* just for grins and giggles and see how that plays on the dyno this next time around.

Just chippin' away at it, little bit at a time.
Because of the timing out of the box for the 37, you will probably not like the -2 degree key. Bottom end tends to stumble and it's like you are waiting for something to happen. But if you just like to play around to get a feel for engine dynamics (which it seems you like to do so that you can get a feel for tendencies on the twin cam, nothing wrong with that) then by all means go for it. But on the STC you will miss the TQ pull on the low R's.

All the Best!
 

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So for the cost of a bore by Andy, (who did my CV Carb on my Sporty and that was a piece of art for sure) and the additional cost of 175.00 for a Duel Runner TB with an existing investment in a true duel exhaust, wheres the smart place to spend the money?
 

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Where's the best place to spend your money??? It all spends the same LAF. Are you satisfied with what you got is the money question.
(gotta twist the blade on this thread though--Edelbrock kit is looking more cost effective as time passes on "conclusive engine dynamics")
 

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kelly said:
Where's the best place to spend your money??? It all spends the same LAF. Are you satisfied with what you got is the money question.
(gotta twist the blade on this thread though--Edelbrock kit is looking more cost effective as time passes on "conclusive engine dynamics")
Thanks. but not the answer.
I guess where is the money best spent on a bore or a duel TB, for my build, is the real question. Which will have the better effect. I think a duel but would like to hear other opinions.
I know how to spend money thank you, I just would like to spend it right, the FIRST time.
 

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GRock said:
Because of the timing out of the box for the 37, you will probably not like the -2 degree key. Bottom end tends to stumble and it's like you are waiting for something to happen. But if you just like to play around to get a feel for engine dynamics (which it seems you like to do so that you can get a feel for tendencies on the twin cam, nothing wrong with that) then by all means go for it. But on the STC you will miss the TQ pull on the low R's.

All the Best!
GRock,
Thank you for the advice! it's relatively easy to switch the cam key around, so I thought I would try it and tune it the best we can and see where it ends up. If I don't like it, I can always put the stock key back in or go back to +2*. You're right though! the low end TQ pull is addictive as he11 and if that were to go away significantly, I surely would miss it.

Any quirks that you know of getting the reworked Delphi TB/intake from Andrew to play nice? I know that the VE tables are going to need revamping, Otto and I will do that on the dyno to get the AFR dialed in. The only problem is, this dyno does not have the eddy current brake to apply load with.
 

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I just bought a 54 mm throttle body (actually the whole intake and induction system) from Zipper's. The 54mm TB is enormous when viewed alongside a stock TB.

Should be just the ticket for my JIMS 120 in motor. :yes:

The pisser is that for $1300 you'd think they would include new injectors. Sadly, this is not the case.

wyo
 

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wyodude said:
I just bought a 54 mm throttle body (actually the whole intake and induction system) from Zipper's. The 54mm TB is enormous when viewed alongside a stock TB.

Should be just the ticket for my JIMS 120 in motor. :yes:

The pisser is that for $1300 you'd think they would include new injectors. Sadly, this is not the case.

wyo
$1300??? OUCH!!! $495 for the BC Gerolamy Dual Runner with 50 mm per side. Smoother idle and low speed and much easier to tune on those fire breathers, too! Especially with the high overlap cams. Probably going to need some larger than stock injectors for that thing depending on the cam. We were able to tune a 124 with the TCFI or SERT, BC dual runner, and larger injectors so that she was real fun to ride.
 

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truck95 said:
Have a '05 FLSTCI w/ 95" kit(flatop pistons),SE air,PCIIIUSB.Will be installing 37g cams,Baisley ported heads w/ 1.900x1.630 valves,RBRacing 2:1 exhaust.My question, does the stock throttlebody put out enough CFM or is it best to upgrade to 48mm or so?With .030 head gasket the comp.ratio is 9.4:1.
I have a 103" Softail making 125 tq and 110 hp through a stock, unbored Delphi throttle body. Admittedly it's too small for what I am running, and I should have it bored out like my other ones. I think at the very minimum you should look at sending it to BC Gerolomy to have it enlarged, or simply go to a larget t-body right from the Get go. That bike could handle a 50mm with no issue.
 

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I did a back to back dyno test on a 3mm overbore stock throttle body on an 88" with a 37G, nice heads ect. 3 hp gain and 2 ft of torque. HP gain was after 5000 rpm. Interestingly enough, bike went rich and I had to lean it out due to the map sensor adding fuel as a result of the increased manifold presure. Fullsac did the TB mod for $150.00. Cheap Hp, but honestly could'nt feel the difference.
RB
 

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GRock said:
Because of the timing out of the box for the 37, you will probably not like the -2 degree key. Bottom end tends to stumble and it's like you are waiting for something to happen. But if you just like to play around to get a feel for engine dynamics (which it seems you like to do so that you can get a feel for tendencies on the twin cam, nothing wrong with that) then by all means go for it. But on the STC you will miss the TQ pull on the low R's.

All the Best!
GRock,
Got off the dyno last night, didn't get everything done but we do know this....
the torque curve shifted about 200 rpm up, down around 2500 rpm but the peak is still at the same spot as before at 3600rpm.

The Dakota Kid Delphi TB/Intake, 1.675:1 ratio rockers and the 2* cam key reversal have not caused a stumble(thank goodness!), the motor is still very responsive and the according to the data, the torque curve has lost 1 ft-lb at the peak but has lifted from 4300 rpm all the way out, compared to before. Old setup crossed 80 ft-lbs at 5400, new setup crosses 80 ft-lbs at 5800. This has added 7 more hp so far and we don't have it totally dialed in yet, we have a few more hp to gain because of learning this AFR stack. It seems to indicate 12.9:1 AFR when my motor makes the most power and we are a touch leaner than optimum right now. Just guessing but we should see a gain of 8-10 hp when everything is done. Final numbers should be around 101-102ft-lbs and 98-100hp, based on what we know right now.
 
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