mk3 escort supercharged st170 box 9/11/10 charger mounted
05-07-2009, 11:03 AM
#1
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mk3 escort supercharged st170 box 9/11/10 charger mounted
this is my car
bike carbed
have removed them for now due to not running right
have these to go on now
my old fiesta
bike carbed
have removed them for now due to not running right
have these to go on now
my old fiesta
Last edited by jonboisescort; 09-11-2010 at 03:49 PM.
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06-07-2009, 07:02 PM
#10
Passionford Addict
06-07-2009, 08:02 PM
#13
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cheers everyone
the new bike carbs are off a gsxr 1100 i think 36mm
also
i used the mechanical fuel pump at first but delivered to much fuel pressure so fitted a regulater but have been having a few probs with this set up
so will be getting a motorbike fuel pump r1 etc
also the inlet manifold is a cut down escort rs turbo inlet manifold
a video of the old bike carbs on
the rattle noise was my thrust bearing
http://www.youtube.com/watch?v=qrs4WS4u7BQ
the new bike carbs are off a gsxr 1100 i think 36mm
also
i used the mechanical fuel pump at first but delivered to much fuel pressure so fitted a regulater but have been having a few probs with this set up
so will be getting a motorbike fuel pump r1 etc
also the inlet manifold is a cut down escort rs turbo inlet manifold
a video of the old bike carbs on
the rattle noise was my thrust bearing
http://www.youtube.com/watch?v=qrs4WS4u7BQ
07-07-2009, 09:15 AM
#15
Bike throttle bodies are designed to work on small capacity very high revving engines, so are not really a wise choice to go on a car, in many cases they could even loose you power, as they don't come 'on song' until well after your car's rev limit.
07-07-2009, 11:02 AM
#19
PassionFord Post Troll
Have you ever fitted bike carbs to a car engine?
I have, several times, and if tuned right they drive much better than most twin 45 equipt cars i've been in.
A set of 40 mm bike carbs would also have the potential to make more power than a set of 45s as in the 45s you have to run a 36/38mm choke!
07-07-2009, 11:02 AM
#20
PassionFord Post Troll
Tell us why then?
Are you refering to carbs again or throttle bodies?
Do you actually know how a CV carb or fuel injection throttle body works??
I hope you don't do the technical advice at your mag?
Are you refering to carbs again or throttle bodies?
Do you actually know how a CV carb or fuel injection throttle body works??
I hope you don't do the technical advice at your mag?
Last edited by Garage19; 07-07-2009 at 11:04 AM.
07-07-2009, 11:07 AM
#21
PassionFord Post Troll
07-07-2009, 12:48 PM
#23
My understanding is that throttle bodies are all about getting the air speed correct for the engine. A bike engine needs high air speed, but not necessarily big volumes of air - whereas a larger capacity, lower revving car engine would need a larger body to allow greater volumes of air, but air speed isn't as important.
07-07-2009, 01:05 PM
#24
PassionFord Post Troll
Of course a bike engine needs a big volume of air! If you have two engines, 1ltr and the other 2ltr they will both need roughly the same amount of air to produce a the same, say 150 bhp, power out put.
07-07-2009, 01:42 PM
#25
The size of the trumpets can be altered to give the bodies more suitable characteristics, but in most car fitments (especially when the inlet is at the rear of the engine) there isn't sufficient space to fit long enough trumpets to make the bike throttle bodies work effectively.
The average length of a 1.0 motorbike system is 70-75mm whereas in a 2.0 car it needs to be nearer to 300mm in total.
A longer system means that the air flow is slower, so it gives the air/fuel mixture more time to mix and as a result gives better mid range power/torque. A bike system is shorter because its primary aim is to get the air into the engine as quickly as possible to allow for the higher revving nature of the engine.
Edit: Sorry about the thread hijack!! Nice car BTW!
Last edited by DanW@FastFord; 07-07-2009 at 02:39 PM.
07-07-2009, 04:58 PM
#27
PassionFord Post Troll
Sorry, but it seems clear you don't quite understand the basics of a four stroke engine. If a 1ltr and 2ltr engine are at the same rpm and have the same VE they cannot and will not be using the same amount of air.
The size of the trumpets can be altered to give the bodies more suitable characteristics, but in most car fitments (especially when the inlet is at the rear of the engine) there isn't sufficient space to fit long enough trumpets to make the bike throttle bodies work effectively.
Right... erm. Don't get your point here. You do not make any sense.
Normal car TB setup eg Jenvey = manifold / TBs / trumpets
Bike setup on car = manifold / TBs / trumpets
How does the bike setup have less space than the Jenveys??? If anything the bike TBs are shorter as they have to be compact on the bike, giving you more space to play with. In a FWD car most times any tuning of resonate frequencies in the inlet is limited by space. This is true if you use bike or car specific TBs. Not to mention that the dyno and development time/cost to carry out frequency tuning is beyond most diy car builders so hardly ever gets done.
The tuned length of you inlet is dependant on a whole host of things like which harmonic you use, desired rpm, cam timing, inlet manifold design etc. Come on Dan, think about it. If you are making your own manifold and haven’t bought any trumpets yet can you think of a way of increasing easily increasing the length of your bike TB inlet??? Hmmm.. Not rocket science is it!
A longer system means that the air flow is slower, so it gives the air/fuel mixture more time to mix and as a result gives better mid range power/torque. A bike system is shorter because its primary aim is to get the air into the engine as quickly as possible to allow for the higher revving nature of the engine.
Although there will be some loss of air speed due to boundary layer friction down a longer system it is primarily cross sectional area and air volume that dictate velocity. It is true that there are some advantages to mixing the air and fuel earlier in the inlet track. The air does not have to be slower for this to be an advantage as you seem to think. If the air speed is too low such as at low rpms the fuel will in fact drop out of the airflow.
A bike system is shorter because of a couple of reasons. Firstly the compact nature of the machine and secondly because at 15,000 rpm the harmonics are at a much higher frequency and require a shorter tuned length.
Surely the aim of all four stroke tuning is to get as much air into a cylinder as quickly as you can… is it not?
Edit: Sorry about the thread hijack!! Nice car BTW![/quote]
Last edited by Garage19; 07-07-2009 at 05:30 PM.
07-07-2009, 05:00 PM
#28
PassionFord Post Troll
All of which are totally configurable if you are using bike OR car specific TBs.
Last edited by Garage19; 07-07-2009 at 05:31 PM.
07-07-2009, 05:01 PM
#29
PassionFord Post Troll
07-07-2009, 05:15 PM
#30
PassionFord Post Troll
cheers everyone
the new bike carbs are off a gsxr 1100 i think 36mm
also
i used the mechanical fuel pump at first but delivered to much fuel pressure so fitted a regulater but have been having a few probs with this set up
so will be getting a motorbike fuel pump r1 etc
also the inlet manifold is a cut down escort rs turbo inlet manifold
a video of the old bike carbs on
the rattle noise was my thrust bearing
http://www.youtube.com/watch?v=qrs4WS4u7BQ
the new bike carbs are off a gsxr 1100 i think 36mm
also
i used the mechanical fuel pump at first but delivered to much fuel pressure so fitted a regulater but have been having a few probs with this set up
so will be getting a motorbike fuel pump r1 etc
also the inlet manifold is a cut down escort rs turbo inlet manifold
a video of the old bike carbs on
the rattle noise was my thrust bearing
http://www.youtube.com/watch?v=qrs4WS4u7BQ
Look carefully at the angle you have mounted them. Yours seem too flat. Most modern bike carbs will only be 35-45 degrees from vertical when on the bike. The angle is critical if you want the floats to work properly. If you set the angle wrong you can get fuel starvation or flooding.
On the subject of fuel pressure you need sod all. You only need enough pressure to deliver the fuel to the float bowl. Alot of bikes do not even have pumps as the gravity from the tank is enough.
If you have too much pressure the fuel will push past the float needles and the engine will run very rich / flood up when starting.
Once you have the car running you start by tuning the main jet first. Odd i know to start with what people think is the top end first but you have to think of this as a global change for all your fuelling. I suggest you start with a 1.6 main jet as a starting point. Then tune your needle height, and idle. Transient fuelling is controlled by the rate the slider lifts so is controlled by air bleeds and the spring.
Give me a shout if you get stuck.
07-07-2009, 05:43 PM
#31
The tuned length of you inlet is dependant on a whole host of things like which harmonic you use, desired rpm, cam timing, inlet manifold design etc. Com on Dan, think about it. If you are making your own manifold and haven’t bought any trumpets yet can you think of a way of increasing easily increasing the length of your bike TB inlet??? Hmmm
Although there will be some loss of airspeed due to boundary layer friction down a longer system it is primarily cross sectional area and air volume that dictate velocity. It is true that there are some advantages to mixing the air and fuel earlier in the inlet track. The air does not have to be slower for this to be an advantage. If the air speed is too low such as at low rpms the fuel will in fact drop out of the airflow
It seems like you've taken my comments out of context to prove your point.
07-07-2009, 06:33 PM
#32
Carb angle does not look too far out IF they are GSXR1100 ones as the engine is fairly vertical on the oil/air cooled Gixers but as Doug has said the angle is super critical, bikes are extremely fussy about float height and need no more than 2PSI of fuel pressure.
Mark
Mark
07-07-2009, 06:58 PM
#33
PassionFord Post Troll
True. I've used GSXR carbs on a pinto before so i could get them and the filter under the bonnet.
07-07-2009, 07:07 PM
#34
PassionFord Post Troll
That's kind of obvious. I was referring to air speed, not air volume.
Yes, but bike TBs have shorter bodies than car bodies. Sure you can configure them to be more suited to car applications, but in general people just bolt a set of bike bodies to their car and leave it at that. Which was my point. You've taken it and turned it into a different argument which I'm not contesting. Your grasp of how TBs work isn't the issue.
Yes, you can alter the length of the inlet with spacers, larger trumpets etc - But the original point was that bike bodies are not as suitable as car bodies.
I don't disagree, but 'in general' would you not agree that longer inlet tracts are better for larger capacity car applications than shorter inlet tracts?
It seems like you've taken my comments out of context to prove your point.
Yes, but bike TBs have shorter bodies than car bodies. Sure you can configure them to be more suited to car applications, but in general people just bolt a set of bike bodies to their car and leave it at that. Which was my point. You've taken it and turned it into a different argument which I'm not contesting. Your grasp of how TBs work isn't the issue.
Yes, you can alter the length of the inlet with spacers, larger trumpets etc - But the original point was that bike bodies are not as suitable as car bodies.
I don't disagree, but 'in general' would you not agree that longer inlet tracts are better for larger capacity car applications than shorter inlet tracts?
It seems like you've taken my comments out of context to prove your point.
"Bike bodies just aren't suitable for cars! "
How can i take that out of context. You have just announced to the world that bike TBs are not suitable for cars.
I've just been trying to show you that no matter what Jenvey have told you, bike bodies are suitable for cars.
I don't think you understand that air speed is totally linked to air volume and the CSA of what it passes through. It doesn't matter if that air volume is pumped by a big pump going slowly or a small pump going fast.
Last edited by Garage19; 07-07-2009 at 07:10 PM.
07-07-2009, 07:15 PM
#35
PassionFord Post Troll
Jon,
Having had a closer look at the pics i can see that the carbs you have on the engine at the mo are GSXR carbs. The carbs that you say you are yet to fit look like they are off something else. They are of the type that will need a steep angle by the looks of it. I would stick with the GSXR carbs if you do not want to make a new manifold.
Having had a closer look at the pics i can see that the carbs you have on the engine at the mo are GSXR carbs. The carbs that you say you are yet to fit look like they are off something else. They are of the type that will need a steep angle by the looks of it. I would stick with the GSXR carbs if you do not want to make a new manifold.
07-07-2009, 08:57 PM
#39
A 1000cc bike engine pulling 12,000 rpm pumps 6,000 litres of air per minute assuming 100% VE
A 2000cc car engine pulling 6,000 rpm pumps 6,000 litres of air per minute assuming 100% VE
Pretty good case for using bike bodies from my point of view, they are fairly cheap and come in plenty of sizes.
Mark
A 2000cc car engine pulling 6,000 rpm pumps 6,000 litres of air per minute assuming 100% VE
Pretty good case for using bike bodies from my point of view, they are fairly cheap and come in plenty of sizes.
Mark
12-07-2009, 05:28 PM
#40
I'm Finding My Feet Here Now
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bike carbs rule 
after nothing but problems with the old carbs i decided to start again
with another set off a gsxr 750 ??
they are 36mm were as the old ones were 34mm carbs
i have used the old manifold for now
they main problem i had was with the fuel pressure being to high form the mechanical pump
so sourced a r1 fuel pump off ebay lastnight and collected that today
they are prity much ready to go back on just need to get a mountain bike gear cable
price of new setup
gsxr carbs 36mm with trumpets £50 :Q
r1 fuel pump £25
inlet manifold £20
other little pices £10
total £105
after nothing but problems with the old carbs i decided to start again
with another set off a gsxr 750 ??
they are 36mm were as the old ones were 34mm carbs
i have used the old manifold for now
they main problem i had was with the fuel pressure being to high form the mechanical pump
so sourced a r1 fuel pump off ebay lastnight and collected that today
they are prity much ready to go back on just need to get a mountain bike gear cable
price of new setup
gsxr carbs 36mm with trumpets £50 :Q
r1 fuel pump £25
inlet manifold £20
other little pices £10
total £105