Question about throttle bodies

[Matty_d]

Here is my current build.
2009 FLHTCU, 107 CI,
Suburban Speed pistons 4.4cc
S&S 91cc heads milled to set 10.8 comp,
T-Man 5902PS cams
SE 58mm TB 5.8 injectors
Stock Catless headpipe, Supertrap slipons
Power Vision and Target Tune

Now my question is, would my lower end RPM be better with the stock 50mm TB and stock injectors? The bike is kind of a dog till it hits roughly 3200rpm. I know the intake ports are larger on the heads than the 50mm tb. Would that cause an issue?

[lonewolf]

Now my question is, would my lower end RPM be better with the stock 50mm TB and stock injectors?

No, if tuned properly

[rigidthumper]

Short answer? No.
Have you had it on a drum to see where you are at? That combo should peak near 120ish, if allowed to breathe. A D&D Fatcat or Dragula would help tremendously. If you want quiet, find a set of Crusher Mellows and match them to a Fullsac DX headpipe.

[Matty_d]

I have had it on the dyno. Not happy with the results.

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[rigidthumper]

A cam change would pick up the left side, at the expense of the right. How much time do you spend at/above 5500?

[Matty_d]

A cam change would pick up the left side, at the expense of the right. How much time do you spend at/above 5500?

Might hit 5500 once and a while, but not very often.

[Coyote]

Did you tune the number of discs on the Trapp?

Your build is pretty close to mine although mine was a 113"

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[Matty_d]

Did you tune the number of discs on the Trapp?

There are no discs on these slip ons. I don't know which ones they are but I know they are from 2009.

I know I need a better tune but want to make sure things are right before I look for a better tuner.

[Coyote]

The 590 does lean to the right but I suspect you also have a tuning issue.  I have no idea about your exhaust setup. I'm sure some of the tuners here would know better.

[No Cents]

  you have the wrong cam choice...if you wanted more off the bottom. The exhaust pipe is also a major player in the game.
The SE 58 and injectors should be perfect for your build.

[Barrett]

If your gear ratio is like my 08 fxdf @2.79:1 regearing would be a good option

[TorQuePimp]

I've had more than one build on that Dyno...... middle of the road imo

I would confirm you have 10.8:1 first

Agree with Robin......should be minimum high teens to 120 horse....tq depending on pipe should be close to 120

The tb is not hurting you at all.......stock 08 tbw to Hpi 58 is +24 cfm and 6 feet per second different......leave that alone

[Deye76]

"I've had more than one build on that Dyno...... middle of the road imo"

Agree, had my 2004 RG on that drum, came away spark knocking, took it back, only slightly better. Wasn't the build, as I took it to another tuner, ran great.

[ThumperDeuce]

My 107" build made 100lbft at 2k with a Wood 400G and some head work by UnderGround Heads.

[doctorevil]

coyote what pipe on that dyno graph? I have same build as you difference from yours woods777 branch heads red thunder pipe almost identical graph torque a little to the left.

[sfmichael]

Did you tune the number of discs on the Trapp?

Your build is pretty close to mine although mine was a 113"

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getting ready to build a 110 with the 590 but am definitely interested in low end torque
do you feel it's not a good cam for that?

[kd]

Depends on your compression and gearing.  The compression feeds early torque and the gearing tricks into showing up even earlier. More compression may require a tighter quench, compression releases and a good tune.  The lower gearing (surprisingly) may give you better mileage.

[sfmichael]

I'll squeeze it as hard as possible but I'm @ 6000' and even if I build it to have 210-215 ccp @ sea level I'll be below 200 here

[Matty_d]

Well, going to have to have a word with my guy at Suburban. Did a compression test today and am only at 185psi.

[kd]

Check it with another "known" to be good gauge first.  Compression tester gauges seem to be all over the map.

[Matty_d]

Check it with another "known" to be good gauge first.  Compression tester gauges seem to be all over the map.

Agreed, but I looked and the invoice from the build and they put in a 0.04" head gasket instead of 0.03". I was told he was going to mill the heads and set it up for 10.8:1.

[Matty_d]

Spoke with the guy that built the engine. Confirmed some details of the build. Heads are at 84.6cc. Front and rear pistons are both 0.006" in the hole. So with the 0.04" head gasket, that puts the compression mathematically at 10.77:1. and 201.2ccp. Taking it back to him to have him do a ccp and leak down test on to. Also going to put it back on the dyno to work on the low end.