Turbo v bike carbs
- Thread starter karlj
- Start date
OP
OP
I knew they would be completely different, I just can't make my mind up which way to go, I have majority of the parts to go with either option
Build wise the carbs will be quickest but a right pita to get running right but I love the whine of a turbo spooling
I might be a little optimist with the figures but at a guess I could see
120bhp with the carbs
150bhp with a turbo
BUT I what to keep it sensible(ish) as a daily with mild track use
Build wise the carbs will be quickest but a right pita to get running right but I love the whine of a turbo spooling
I might be a little optimist with the figures but at a guess I could see
120bhp with the carbs
150bhp with a turbo
BUT I what to keep it sensible(ish) as a daily with mild track use
Each have pros and cons and opinions will differ depending on who you talk to, what their motivation is and how much cash they have to put up, but 120bhp with carbs is a lot less risky than 150bhp with a turbo, (with the obvious lack of that rocketship feeling a turbo delivers). You also don't have to bother upgrading the clutch, as you wont be generating much more torque, just shifting it up the rev range due to vastly improved engine breathing. I believe Skinner_87 in here has a carb setup on his CG13DE K11 running well, so he should be able to give you some pointers and experiences.
Having had direct experience with throttlebodies I can say our setup was very drivable and made more torque across the entire rev range compared to stock, (Jenvey 48mm taperbores and Matt Humphris '773' cams). Many people will tell you that you lose low end but that is just an old wives's tale. You'll will lose some torque with carbs compared to throttlebodies but it shouldn't be much to be honest and I am sure the outlay will make them much more attractive, (ITB's aint cheap)......fuel economy could be an issue perhaps as will the faffing come MOT time to pass emissions. There's also the issue with not being able to optimize the ignition timing properly but most things have their compromises unless you have the cash for a mappable system and many people on here are more than happy to make those compromises to avoid 'costly' remapping.
Having had direct experience with throttlebodies I can say our setup was very drivable and made more torque across the entire rev range compared to stock, (Jenvey 48mm taperbores and Matt Humphris '773' cams). Many people will tell you that you lose low end but that is just an old wives's tale. You'll will lose some torque with carbs compared to throttlebodies but it shouldn't be much to be honest and I am sure the outlay will make them much more attractive, (ITB's aint cheap)......fuel economy could be an issue perhaps as will the faffing come MOT time to pass emissions. There's also the issue with not being able to optimize the ignition timing properly but most things have their compromises unless you have the cash for a mappable system and many people on here are more than happy to make those compromises to avoid 'costly' remapping.
OP
OP
which ever way I was to go I'd get it set up properly.... luckily I live near a mini tuner who I believe has experience with setting up bike carbs (going to get hold of him in the new year to double check)
I could run the carbs as ITB's but i think that'll be more hassle than it's worth, unfortunately I don't have the same sort of budget as you LR but that doesn't mean I'd be doing it "cheap"
I could run the carbs as ITB's but i think that'll be more hassle than it's worth, unfortunately I don't have the same sort of budget as you LR but that doesn't mean I'd be doing it "cheap"
pollyp
Club Member
Bike Carb:
PRO
instant response
broad power gain
CON
gain dependent on rest of the system especially exhaust but not potentially as high as turbo other than going towards an expensive screamer route
Turbo:
PRO
potentially larger gains(small turbo for low-end torque but restricted high end, big turbo for high-end torque but higher boost threshold. matching turbo config with ur engine for ur needs is important)
CON
high torque & power may require stronger clutch upgrade
may need cooling system upgraded due to extra heat(especially on trackdays)
more frequent oil change
must let turbo & oil cool/spool down before shutdown
at high power level the stock AFM may have maxed out so will need a larger AFM sensor (e.g. GTIR AFM)
risk of instant power loss during high load demand (overtaking lorry?) from rupturing IC piping or overboost engine damage (failed boost control)
both setups may have altered AFM & TPS readings so you'd need to tune the ECU anyway either intercept & correct the ECU inputs or remap the stock ECU with a daughterboard (recommended) or tune a dedicated ECU (£££). tuning difficulty depends on knowledge, experience and available resources of the person doing it.
gtsnissanb
Official MSC Trader
If you have enough parts to go either way, why not do both? Bike carbs are generally pressurisable iirc so won't have any issues running boost
OP
OP
I would but I doubt there's enough room to run hoses to the carbs without hitting the bulk head
OP
OP
God damn it now I'm looking at turboing the bike carbs grr grr
Small turbo into a plenum chamber(instead of air filter) would work but wouldn't I end up killing the engine if I didn't forge the internals? Also I'm going to be raising the compression so without a good remap I'm almost certain it WILL go BANG
Small turbo into a plenum chamber(instead of air filter) would work but wouldn't I end up killing the engine if I didn't forge the internals? Also I'm going to be raising the compression so without a good remap I'm almost certain it WILL go BANG
http://www.youtube.com/watch?v=TM6TCGltfHM&ob=av2e
Seems like a lot of people felt in love with carbs seeing this vid:
http://www.youtube.com/watch?v=absHX6fO9kw&sns=fb
Seems like a lot of people felt in love with carbs seeing this vid:
http://www.youtube.com/watch?v=absHX6fO9kw&sns=fb
OP
OP
gtsnissanb
Official MSC Trader
That's what I was gonna do before sr20bud bought my cbr carbs
Don't see why you'd need to forge anything just run low boost with a t2 from a FRST
Don't see why you'd need to forge anything just run low boost with a t2 from a FRST
frank
Club Member
+1 and carbs on and injected car are a backward step fwn pre-war technology ffs
i,ve shown that the maf works fine pre turbo, so leave the injectors in karl and use the carbs as quads
-1 Carbs 'work', they're ghetto and they don't require any 'costly' remapping.......don't be a hater
Nos
frank
Club Member
low rider is right technically. multi-point fuel injecting with electronic mapping is still only 15 to 20 years old (group B rally started playing with it) so its only developed so far. carbs have been played with for the last 80 years and their design is near perfect. i know there are drawbacks, like it still fuels off throttle, but that just gives it pops and bangs.
secondly, i agree with Frank! better to gut out a set of carbs and use them as ITBs.
You should be able to "remap" the car yourself with an adjustable fuel pressure regulator. if you've added a load more air obviously you'll need more fuel as well so whop up the pressure, with reference to afr. it doesnt matter that the ecu thinks its on standard fuelling because the fuel rail pressure isnt controlled electronically. i know it isnt particularly accurate, but its definitely cheap!
last but not least, turbo cooling! you DO NOT NEED a turbo cooler/timer for a micra. boosting a micra with standard internals you might be lucky (with the ITBs) to push 7 or 8 psi of boost. i know people with Nissan 200s and 300s, one of which runs 26psi. he's the only one over 25psi and also the only one with a timer. i once read bout a guy with an evo, put an EScos 2L lump in it and boosted to 43psi!
secondly, i agree with Frank! better to gut out a set of carbs and use them as ITBs.
You should be able to "remap" the car yourself with an adjustable fuel pressure regulator. if you've added a load more air obviously you'll need more fuel as well so whop up the pressure, with reference to afr. it doesnt matter that the ecu thinks its on standard fuelling because the fuel rail pressure isnt controlled electronically. i know it isnt particularly accurate, but its definitely cheap!
last but not least, turbo cooling! you DO NOT NEED a turbo cooler/timer for a micra. boosting a micra with standard internals you might be lucky (with the ITBs) to push 7 or 8 psi of boost. i know people with Nissan 200s and 300s, one of which runs 26psi. he's the only one over 25psi and also the only one with a timer. i once read bout a guy with an evo, put an EScos 2L lump in it and boosted to 43psi!
Cosworths always need mega boost to make any decent power.
Carbs maybe argued as backward compared to EFI, however having an EFI system and not using to it's full potential is also backward.
How much people are prepared to PAY could perhaps be considered more relevant, eh Frank
Carbs maybe argued as backward compared to EFI, however having an EFI system and not using to it's full potential is also backward.
How much people are prepared to PAY could perhaps be considered more relevant, eh Frank
pollyp
Club Member
Could ya be more specific on ease of living with?
If ya mean maintainance, n/a is more reliable n easier n less hassle.
If ya mean ease of climbin inclines or overtaking on motorway, I'd have to rev an n/a in lower gear with loadsa throttle to get enough torque whereas a turbo i just have to nudge the pedal to add a little boost and it climbs with ease.
Drivability, how the engine responds to ur demands- you'll eventually adjust ur driving style to suit.
My 1.3 160bhp & ftlb turbo with 3 paddle clutch and 2-way lsd i drive daily may not be the easiest to drive initially compared to a stock one but I soon learn n adapted to it just like driving any other car
If ya mean maintainance, n/a is more reliable n easier n less hassle.
If ya mean ease of climbin inclines or overtaking on motorway, I'd have to rev an n/a in lower gear with loadsa throttle to get enough torque whereas a turbo i just have to nudge the pedal to add a little boost and it climbs with ease.
Drivability, how the engine responds to ur demands- you'll eventually adjust ur driving style to suit.
My 1.3 160bhp & ftlb turbo with 3 paddle clutch and 2-way lsd i drive daily may not be the easiest to drive initially compared to a stock one but I soon learn n adapted to it just like driving any other car
solarice
Ex. Club Member
Man are you gonna have a hard time getting a concensus on this lol.
Ease of use are probably the same (once you get to know the cars mood again), its just your maintenance routine that will probably change slightly.
As i've built a boosted one, personally i'd now like to try build a N/A screamer...
Do you have the parts already to go carb? if its only gonna cost a little bit in fabrication have a shot...cant comment on what you do ecu wise to let you achieve that though.
Ease of use are probably the same (once you get to know the cars mood again), its just your maintenance routine that will probably change slightly.
As i've built a boosted one, personally i'd now like to try build a N/A screamer...
Do you have the parts already to go carb? if its only gonna cost a little bit in fabrication have a shot...cant comment on what you do ecu wise to let you achieve that though.
solarice
Ex. Club Member
Yup and just keep going til you get the correct side.
Actually I dont think theres been a proper decision on turbo vs sc and thats been going on from before i started the build on mine lol.
gtsnissanb
Official MSC Trader
Tell that to the R5gtt guys then, the point of both will Is that he has the parts for both, so why not fit both? It's easier to do one or the other yeah, but why follow the crowd?
frank
Club Member
How much people are prepared to PAY could perhaps be considered more relevant, eh Frank
some of us get satisfaction from resolving an issue with hands-on cunning, others just write out another cheque eh
Im a deffinate +1 for carbs Karl (nothing against turbos at all, like Frank has said in post #2 i went for the track screamer option) i would say the bad points for a daily driver is the impact on mpg & the noise..
The sound they make is brilliant & not too bad when your wearing a helmet but driving around town, long drives i could see them being tiresome after a while! Also to im not sure if it would upset emissions for an MOT? dont have them here so carnt say sorry
(nothing against turbos at all, like Frank has said in post #2 i went for the track screamer option) i would say the bad points for a daily driver is the impact on mpg & the noise..The sound they make is brilliant & not too bad when your wearing a helmet but driving around town, long drives i could see them being tiresome after a while! Also to im not sure if it would upset emissions for an MOT? dont have them here so carnt say sorry
pollyp
Club Member
Im a deffinate +1 for carbs Karl
The sound they make is brilliant & not too bad when your wearing a helmet but driving around town, long drives i could see them being tiresome after a while! Also to im not sure if it would upset emissions for an MOT? dont have them here so carnt say sorry
ah yeah forgot to mention,
turbo economy will be lower cos u have to run high octane to prevent detonation so more £ per litre,
high boost pressure requires more fuel which could reduce mpg depending on efficiency of setup & mapping
the urge to push the pedal is very tempting
noise depends on the chosen exhaust & BOV setup.
running large straight through system with little silencing/resonance for less backpressure is obviously louder than a silence baffled one. some say the turbine itself also helps to muffle exhaust noise energy.
dump valves are obviously gonna HISS louder and lose turbo response between gearshift compared to a quieter recirc valve.
emissions-wise even with the secondary cat under the gearstick which doesn't get hot enough to work, i found it really difficult to pass emissions test and have to swap to n/a every year for MOT. bear that in mind.
gtsnissanb
Official MSC Trader
I get Much more MPG using higher octane fuel than regular pump fuel, also generally wouldn't adding a turbo not effect fuel at all if you keep it out of boost, but carbs will reduce mpg constantly, also I thought turbos generally lower emissions and you check the emissions at a steady rpm so you won't be boosting or adding extra fuel
some of us get satisfaction from resolving an issue with hands-on cunning, others just write out another cheque eh
We're all satisfied in different ways. I'll take well thought out engineering based principles over hands-on cunning every time and let those 1/4mile times speak for themselves
+1 with Solarice, it doesn't look like you are going to get much of a general majority on this one karlj. Best of luck with whatever route you take though and a merry xmas & new year to you
Yeah I got that a little while ago lol, but I'm enjoying the debate
Merry christmas to all and and a happy new year
Not much on the debate karlj............plenty of hot air though eh
frank
Club Member
Not much on the debate karlj............plenty of hot air though eh
nah, just a bit of psyching up for next years santa pod showdown eh dave
maybe even ed will get his finger out, and run that ST too
nah, just a bit of psyching up for next years santa pod showdown eh dave
maybe even ed will get his finger out, and run that ST too
Hehe, yeah man, really looking forward to it.......not sure how many trips I can wangle over to the UK but will try to slot in a POD meet. Really concentrating on JAE 2012 though, just hope they choose the 7th-9th Sept weekend.
Ed'll get that ST going one of these days but work is proving to be the priority.......very easy 13's potential in that lump.
Will you be making another home brew tubby setup? Arghh, talk about hijacking karlj's thread.....sheesh!
