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Discussion Starter · #1 ·
Garret GT2554R were ok with 1130cc but what turbo are V-Rod guys using with larger displacements and better flowing configurations. Small turbo has become to its limitations
 

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Discussion Starter · #3 ·
Thanks for the reply Freudie.

I can go up to 1,2bar boost but normally I keep there 0,8 to 1,0bar. I have used 8800rpm limit since it is 1/4" stroker. Intercooler is also used.

It performs well in the low end and high end. With the low throttle cruising speeds it is awful. It cannot be cured with the tune anymore. It's been tuned in the dyno and the streets. Many specialists here thinks that especially turbine in 2554 is way too restrictive with my head flows now. Especially it is V2 not inline four. There is wall after cyls when turbo is not spinning with high velocities.

I am planning to go with bigger turbo but not decided yet which one is good for 1350.
 

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Discussion Starter · #5 ·
Sure. Here is couple of snapshots of my current setup. Oil and fuel pressure gauges are just for initial dial in. Normally they are not there.

I have calculated that I need approx. 32 to 36 lb /min flowing compressor and suitable turbine as well.

Borg&Warner have great turbo matching bot on their site. Maybe aluminium core single scroll EFR-6758 would be one possible choice. If I go bigger I have some fitting problems. I do not want too big bucket hanging on my side.

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Discussion Starter · #7 ·
Thanks. Temps are not really problem since I run with E85 gas. Highest I've seen is 94C (201F) and that is in traffic jam or idling long time. At cruising speeds it is normally 82C (180F). Fan is on at 93C (199F).

But it can be seen that exhaust gasses are hot. Turbine and down pipe has got some heat and discolored. Maybe I should put egt there for eximination. That could also be one sign of too small turbine as well. Of course by abusing the engine they will change color almost to red anyway.

T-bolt clamps may not be the prettiest solution but they are effectively sealing the silicon connectors to pipes. Especially if there is no bump in the pipe end.

BOV is still outside because covid-19 delayed my internal Forge version shippings. I will relocate it outside riding season to plenum side.
 

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Discussion Starter · #9 ·
Where'd you get/make that plenum!
It is Swedish MCXpress plenum. I think it is great too. There is possibility for two additional shower type injectors on the top. I am figuring out how to use them someday. Now they are plugged. There is integrated oil catch can in the front but air volume for intake is still good for equal cyl flow.
 

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Where'd you get/make that plenum!

biggest problem i have with trask and holymoto is the plenum size.
Like the TTS option for that that reason but criminy your's is prettiest ive seen in a while!
Mukle beat me to it...looks like Kaarza's/etc. I am almost designing my own which is similar to Holy Moto's but with some fairly significant changes (and a feature no one else offers).
 

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Discussion Starter · #11 ·
No need to start punching. You have sharp eyes Freudie but no plenum is not Karzza's K&M. I've bought it from mcxpress. It is great Swedish company with wide range of turbo applications.

However turbo is Karzza's old. We have been made projects together now for several years. I am very honored to know someone with those skills and technical knowledge. He is strong influencer in my projects and this could have not been done without him. Therefore you can see some similarities there.
 

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Discussion Starter · #13 ·
Santa came early this year and brought me a puzzle ;) Alucore is lightweight compared to cast iron. Gamma-Ti turbine wheel is very light as well. Pretty sure that its low rotational inertia will be seen in fast spooling. Guys in the United States really know how to make high performance turbo's. Hope that with this I could hit 300 pony marker one day.

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Discussion Starter · #14 ·
New compressor is larger as expected. Old compressor wheel exducer was 54 and the new is 61,4. Reading from compressor map old were good for 270hp with reasonable effiency but B&W should be good up to 450hp.

Of course those numbers will not never measured out but one restriction less. What I am really looking for is snappy nature by quicker turbo spooling.

I like idea using integrated BOV and get rid of those ugly external blocks. Also electrical boost controller might be handy someday. Have no idea how to implement it yet. Maybe at first I will just block it. All suggestions are welcome of course.


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Discussion Starter · #15 ·
Making some room for the larger compressor. So goodbye main switch bracket. I will use that cavity between head and frame to sink compressor as much as possible.

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I was always told the larger the compressor the longer the lag and less snappy down low. Along with slower spooling
 

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Discussion Starter · #17 ·
I was always told the larger the compressor the longer the lag and less snappy down low. Along with slower spooling
Can be. I'm just following my intuition here. However things are not so straightforward and the case is rather complex. Whole engine is built for turbocharging so I want to choose best turbo option for my application. Of course this can lead to ashes as well.

And if no one would test you would never now ;)
 

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My engine is also built for turbocharging and went with smaller turbo just to make the low end from 2k up "snappy" and will break the rear tire loose at 75mph in 3rd with a 30 tooth front pulley at half throttle. I have researched this for years before moving forward. One wrong piece to the puzzle will make you chase your tail.
 

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Discussion Starter · #19 ·
That will be seen. Old turbo was pretty ok with the stock displacement but with the sturdy good flowing 1357cc stroker it just came to its limitations. Compressor power band was relatively narrow compared to EFR's band and it was hard to stay in good operation region. New compressor should be now almost anti-stalling and there is enough top flow with the good effiency. These can be seen when comparing compressor maps. Have to realize this in real life too.

EFR 6258 ain't that big turbo yet so I am not very concerned that it is too big yet. It's design is just from the different planet when you compare parts like turbine wheel and aluminium chra on whole. Turbine is made of Gamma-Ti material weights half of the old one. I hope that this will help on low end awakening and lag which all turbos suffer in some extent.

If this turns out shitty I can always come back but building and testing things is part of this hobby. I do not buy things without chewing them a bit. Every day is hard way learning and I do not take this too seriously.
 

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That will be seen. Old turbo was pretty ok with the stock displacement but with the sturdy good flowing 1357cc stroker it just came to its limitations. Compressor power band was relatively narrow compared to EFR's band and it was hard to stay in good operation region. New compressor should be now almost anti-stalling and there is enough top flow with the good effiency. These can be seen when comparing compressor maps. Have to realize this in real life too.

EFR 6258 ain't that big turbo yet so I am not very concerned that it is too big yet. It's design is just from the different planet when you compare parts like turbine wheel and aluminium chra on whole. Turbine is made of Gamma-Ti material weights half of the old one. I hope that this will help on low end awakening and lag which all turbos suffer in some extent.

If this turns out shitty I can always come back but building and testing things is part of this hobby. I do not buy things without chewing them a bit. Every day is hard way learning and I do not take this too seriously.
How are you handling prevention of block shift with this much power? I know Kaarza went to the extremes with dowels/larger bolts/etc.....never heard if it really held up. Are you rebuilding every couple thousand miles?
 
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