Topic: Size throttle body for 120R (Read 12128 times)

SDCVO · « **on:** July 04, 2013, 01:24:42 AM »

After over a year of torturing myself over what upgrades to do to my motor I have finally decided to go with a new crate 120R. I have seen people recommend the 58mm but looking for advice. I am still looking for "bottom end"...

hd-dude · « **Reply #1 on:** July 04, 2013, 01:31:53 AM »

The SE 58mm is the best bang for the buck. Add the 5.3 injectors as well.....

Twolanerider · « **Reply #2 on:** July 04, 2013, 01:34:44 AM »

Quote from: SDCVO on July 04, 2013, 01:24:42 AM

After over a year of torturing myself over what upgrades to do to my motor I have finally decided to go with a new crate 120R. I have seen people recommend the 58mm but looking for advice. I am still looking for "bottom end"...

One of the happiest campers I know with a nicely touched up 120R is Scott Dunbar. Here's his post from about a year ago well in to the service life of his engine and describing what he did after getting it to really dial it in:

Quote from: sadunbar on August 20, 2012, 01:19:26 PM

If it's a 2012 - 120r motor, it has the upgraded billet cam plate and high volume oil pump. The lifters are SE lifters, but are not made by JIMS.

When I installed my 120r, I replaced the cams with T-Man 662-1 cams, upgraded the clutch with a BDL kit (purchased from Jim) along witha VPC 92T variable clutch kit, installed a 55mm HPI throttle body with 5.3 injectors and installed a Jagg 10 row oil cooler...

I'm at 15K on the motor and am happy!

sadunbar · « **Reply #3 on:** July 04, 2013, 02:34:10 AM »

Quote from: Twolanerider on July 04, 2013, 01:34:44 AM

One of the happiest campers I know with a nicely touched up 120R is Scott Dunbar. Here's his post from about a year ago well in to the service life of his engine and describing what he did after getting it to really dial it in:

The 55mm HPI throttle body I run flows very similar to the 58mm SE throttle body Jim suggests.

IMO either is a good choice for the 120R.

For what it's worth, I started out with a 62mm HPI throttle body on my 120. The low speed driveability of the 55mm HPI throttle body is much improved as compared to the 62mm HPI throttle body. I had the bike on the dyno with both and there was very little difference in the results in the RPM ranges I actually ride in. The 62mm produced slightly better numbers at WOT. The 55mm produced better numbers down low...

prodrag1320 · « **Reply #4 on:** July 04, 2013, 07:52:49 AM »

we`ve used the 58mm on the 120R`s with very good results,guys are very happy with them

jlsnyderCVO · « **Reply #5 on:** July 04, 2013, 09:16:58 AM »

I'm running a 58mm on mine and I've got no complaints.

hrdtail78 · « **Reply #6 on:** July 04, 2013, 12:34:04 PM »

Quote from: sadunbar on July 04, 2013, 02:34:10 AM

The 55mm HPI throttle body I run flows very similar to the 58mm SE throttle body Jim suggests. IMO either is a good choice for the 120R.

For what it's worth, I started out with a 62mm HPI throttle body on my 120. The low speed driveability of the 55mm HPI throttle body is much improved as compared to the 62mm HPI throttle body. I had the bike on the dyno with both and there was very little difference in the results in the RPM ranges I actually ride in. The 62mm produced slightly better numbers at WOT. The 55mm produced better numbers down low...

We have seen the same here. One major plus about the HPI 55 is you are not pigeon holed into air cleaners.

HD Street Performance · « **Reply #7 on:** July 04, 2013, 12:39:39 PM »

Depends on your goals and the level of tuner at your disposal.
The SE58 is a good commodity grocery getter and a throttle hog by S&S offers more even with the OEM cam. The throttle hog is at a very good price point too.

JohnCA58 · « **Reply #8 on:** July 04, 2013, 01:06:10 PM »

Like Don says, the tune is what makes or breaks it, I also very happy with my HPi 55 and produce great hp and tq. I am using the HPi 6.2 injectors throttle sensitivity was important to me, this is a everyday bike. the 55 is manageable.

SDCVO · « **Reply #9 on:** July 04, 2013, 01:07:25 PM »

Quote from: Deweysheads on July 04, 2013, 12:39:39 PM

Depends on your goals and the level of tuner at your disposal.
The SE58 is a good commodity grocery getter and a throttle hog by S&S offers more even with the OEM cam. The throttle hog is at a very good price point too.

What size throttle hog would you suggest then, 58mm?

SDCVO · « **Reply #10 on:** July 04, 2013, 01:09:58 PM »

Quote from: JohnCA58 on July 04, 2013, 01:06:10 PM

Like Don says, the tune is what makes or breaks it, I also very happy with my HPi 55 and produce great hp and tq. I am using the HPi 6.2 injectors throttle sensitivity was important to me, this is a everyday bike. the 55 is manageable.

Does anyone know of "that guy" to tune it in the San Diego area? I completely agree that is is hugely important!

HD Street Performance · « **Reply #11 on:** July 04, 2013, 01:24:08 PM »

Perhaps Cycle Visions
58 or 66mm either
The nice part of the TBW is it can be buffered to cure parking lot manors at low speeds.
The 120R I helpd a guy in Mich. with, heads and build design went 148hp/130 and that was with the stock cam.
It has a 66mm TB and 201 CCP compression, Wengler 2:1.
One other 120r "B" motor that got switched to 124" same heads and same CCP with 662-2 cam went 140/146 with 58mmTH and Boarzilla with Trapp IIRC. Big fat torque curve on this one.
Consider the lower torque number on the first as a result of the pipe mainly, it is huge. The torque curve was flat however and was still far over 100 at 5500rpm.

SDCVO · « **Reply #12 on:** July 04, 2013, 03:42:31 PM »

Quote from: Deweysheads on July 04, 2013, 01:24:08 PM

Perhaps Cycle Visions
58 or 66mm either
The nice part of the TBW is it can be buffered to cure parking lot manors at low speeds.
The 120R I helpd a guy in Mich. with, heads and build design went 148hp/130 and that was with the stock cam.
It has a 66mm TB and 201 CCP compression, Wengler 2:1.
One other 120r "B" motor that got switched to 124" same heads and same CCP with 662-2 cam went 140/146 with 58mmTH and Boarzilla with Trapp IIRC. Big fat torque curve on this one.
Consider the lower torque number on the first as a result of the pipe mainly, it is huge. The torque curve was flat however and was still far over 100 at 5500rpm.
Do you know the guy at Cycle Visions?

TorqueInc · « **Reply #13 on:** July 04, 2013, 04:50:17 PM »

Throttle hog....price be damned its a much better tbody than the se airflow wise and has recently proven itself to make more power.

And as Jason said it does suck that the AC options aren't great

RayG · « **Reply #14 on:** July 04, 2013, 09:15:24 PM »

I also have the 66mm TB, but I went with the S&S 124. The 58mm can usually be purchased at a decent price. The S&S Throttle Hogs have to be sent back to S&S so if time is important you will have to consider that. In my case it was cheaper to have my 50MM sent out to S&S to be modified but I would have no problem using the 58.

HILLSIDECYCLE.COM · « **Reply #15 on:** July 05, 2013, 10:12:57 AM »

We've installed the 66 mm S&S T/H's on modified 120R's.
They seem to work fine.
Scott

HD Street Performance · « **Reply #16 on:** July 05, 2013, 10:23:50 AM »

It will take the carb guys another few years to figure out that an EFI motor with high piston flow demand can use larger throttle area and that is the Achilles heal that is taking these motors to new heights by building higher VEs. The plenum acts like a Helmholtz.

SDCVO · « **Reply #17 on:** July 05, 2013, 11:12:46 PM »

OK, how about any good (great) tuners in the Orange County area? Not having much luck in San Diego... Even southern Los Angeles would work if needed

hrdtail78 · « **Reply #18 on:** July 06, 2013, 01:05:02 AM »

FWIW Have you considered what exhaust you plan on running. A 66 throttle hog will do great with a Wegner exhaust. Both are made to make HP. Put on a better set of pipes for TQ, and the 66 throttle hog won't be a benefit. As others can explain better. If the exhaust valve stalls at 130. No bolt on is going to help. Throttle blade control helps a bunch in TBW, but remember. It is a percentage. 7% of 55 and 7% of 66 is different.

Emmet Otter's Jugband is where I want to hear my Helmholtz.

SDCVO · « **Reply #19 on:** July 06, 2013, 01:08:02 AM »

Going with a Boarzilla..

sadunbar · « **Reply #20 on:** July 06, 2013, 06:02:22 AM »

Quote from: hrdtail78 on July 06, 2013, 01:05:02 AM

FWIW Have you considered what exhaust you plan on running. A 66 throttle hog will do great with a Wegner exhaust. Both are made to make HP. Put on a better set of pipes for TQ, and the 66 throttle hog won't be a benefit. As others can explain better. If the exhaust valve stalls at 130. No bolt on is going to help. Throttle blade control helps a bunch in TBW, but remember. It is a percentage. 7% of 55 and 7% of 66 is different.

Emmet Otter's Jugband is where I want to hear my Helmholtz.

Thank you for completing the picture for the OP!

So many get caught up with huge throttle bodies without understanding or explaining the rest of the picture. Big flowing throttle bodies are only worthwhile if the entire package can handle the same flow rate....throttle body, intake, heads, cams, exhaust... That's why I recommend either a 55mm HPI or 58mm SE throttle body on an otherwise stock 120r motor... Good throttle response and good low speed driveability. If you go larger, then expect to do some headwork and to have some big flowing exhaust in order to reap the benefit... And find someone able to tune such a package...

Unbalanced · « **Reply #21 on:** July 06, 2013, 09:28:15 AM »

Scott,

To that mix I would add the 58 Throttle Hog from S&S, IMO it is the best of the 3 out there atm being SE, HPI and S&S and the cost is right as well. I would also point out that too many of the people I have seen are mounting a 50mm OD air cleaner opening on a 58 mm throttle body such as the ventilator air cleaner.

In the case of the heavy breather they can open that up and take the downsizing ring out of the center of it which will help the flow.

mike jesse · « **Reply #22 on:** July 06, 2013, 03:37:19 PM »

Quote from: SDCVO on July 06, 2013, 01:08:02 AM

Going with a Boarzilla..

If you like them loud the Borzilla is fine.
I prefer the V/H Power Duals and Crusher Mellows, much quieter and will handle the requirements of the 120R.

SDCVO · « **Reply #23 on:** July 06, 2013, 11:13:58 PM »

I really like loud which is one of the biggest reasons Im going with it. I think its the loudest?

SDCVO · « **Reply #24 on:** July 06, 2013, 11:15:55 PM »

Ordered everything yesterday, went with the 58mm SE

Author Topic: Size throttle body for 120R (Read 12128 times)