Question For Bodies On A Xu5

[ifcho 0]

Hi,

 

I just bought some GSXR bodies from ebay and now I'm wondering about two things:

 

has somebody actually fittes such TBs to a 1.6, and do you think they be a bit big for such a small engine? These are the bodies:

 

 

I guess they are 43mm

 

 

The second problem is how to fit them to my head. I'm thinking of chopping down the original manifold and using its flange. To it I will weld some aluminium tubes to form a manifold. So far so good, but the shape of the ports on the XU5/XU9 heads is dome type and here I'm not sure what to do.

Should I take the dremel out and make the ports round (I'm not very keen on this idea) or should I think of some adapters to be inserted in the manifold that will gradually change the shape from round to dome?

 

P.S. Do you know what is the port shape of a XU10J2, if they are round or square I may directly go to that option.

[brianthemagical 1]

which gsxr they off? 43mm will be plenty, depending on wht you want, it's more they'll be accepatble at low down than too big. bigger bodies alow effective ram charging at higher rpm's , but if you can make the tract long enough it will bring the power band down but stil keep it quite large.

i have a couple of topics from a few days ago on he subject,but for a 1.9. i was thinkng of getting some ali pipes crushed to the runner shapes and the changing to round for the bodies, need the bodies first.

[ifcho 0]

well, they are 2003-2004 1000GSXR, according to this page: http://www.motorcyclistonline.com/roadtest...zuki_gsx_r1000/

they are:

Carburetion Keihn electronic fuel injection with 42mm throttle bodies

[TVH 0]

I have same kind of bodies but in 38mm size, I'm planning to use a twin carb inlet manifold as a starting point. Another idea was to fabricate the manifold from fibreglass but this would be an extremely bulky job.

[brianthemagical 1]

you need to take into consideration the positioning of the injectors, i.e. as close to standard as poss, and ensure you can get sutible length tracts.

[Guest hassan]

i have also set of throtle bodies from ferrari 430 but my engine is mi16, i think the best way is to make to plates one to the head ports and the other to the bodies flange, then weld 4 tubes between the two plates where they all the same length, for that you must devide the bodies into two groups for 1,2 cylinders group and 3,4 cylinders group and then adapt the two groups to work well together so you can easly make the 4 tubes the same length.

[brianthemagical 1]

i have also set of throtle bodies from ferrari 430 but my engine is mi16, i think the best way is to make to plates one to the head ports and the other to the bodies flange, then weld 4 tubes between the two plates where they all the same length, for that you must devide the bodies into two groups for 1,2 cylinders group and 3,4 cylinders group and then adapt the two groups to work well together so you can easly make the 4 tubes the same length.

 

injectors? fuel rail? they need to attach some how, the std mani lends itself due to the engie angle.

[ifcho 0]

Here is a quote from Jenvey's website:

Where is the best place for the injectors?

Where one injector is to be used per cylinder the best compromise position is immediately downstream of the butterfly. This gains maximum advantage from local turbulence and gives results surprisingly close to the optimum at both ends of the rev-range. This is the recommended position for most applications

For performance at low RPM, economy and low emissions the injector needs to be close to the valve and firing at the back of the valve head. This is the favoured position for production vehicles.

For higher RPM (very approximately 8,000+) the injector needs to be near the intake end of the induction tract to give adequate mixing time and opportunity. The higher the RPM, the further upstream the injector needs to be. As a result, use of speeds above approximately 11,000 RPM may give best results with the injector mounted outside the inlet tract altogether (see our remote injector mounting). It is common to fit both lower and upper injectors in such a system to cover starting and low RPM as well as high speeds.

 

So I'm thinking of leaving the injectors on the bodies. This way they will be exactly behind the throttle buturflys but not too far from the valves, so won't be loosing too much low end power.

Wit the 1.6 however, I'm stuck with high RPM if I want decent power figures so the low end is not of such importance.

 

I'm open to any comments, though

[brianthemagical 1]

point taken. certainly makes the manifold a lot easier. i'm thinking of running 8 injectors, 4 in the bodies and 4in the std positions, if i use the std mani, as i want the low down more. what management are you going to use? keep us updated.

[brianthemagical 1]

to get the best out of the body injectors, you need to put some thought into themanifold, i.e. straight, round pipes can induce rotation and centrifugal seperation, you will also need a rough surface to prevent wetting, amongst other things. there is a ot of design that goes ino manifolds, hence the price of some.

[Sandy 189]

I strongly advice keeing the injectors as near to that valves as possible unless it's a race engine. If you wish to maximise the engine's potential towrds the top of the rpm range, consider fitting twin staged injectors with the inners as close to the avle as possible and the outers as far up the tract as is convenient.

 

I've tried running/mapping injectors in several positions and during normal driving and up to about 80% effort, the OE style position is definitely advantageous to the quality of the mapping, economy, throttle response, emissions and ambient smell from fuel stand off. Unless it's a dedicated road or track car, It is IMO the best way. Twin staged injectors allow you the best of both worlds, better mixing at maximum effort (theoretically, but it seems to bear out in the results) and the smaller injectors are cheaper and provide better fuelling accuracy, especially at low load and idle.

[ifcho 0]

I know you are right Sandy, and I'll try to build a manifold based on the original,and keeping the injectors at the OEM position. I was looking at some 405 gri manifolds, as they look more suitable.

I will start building the engine in a few monts and I'm now waiting for the bodies to arrive and the car is going for a rollcage tomorrow, so there is plenty of time to design a proper induction

 

Thank you

[Sandy 189]

It's just my opinion!

 

The 405 GRi has the downdraught style head doesn't it? If so, the manifold won't fit the 205GTi head.

[brianthemagical 1]

what kind of tract length do you recomend? i was thinking something like the same as the runners to the plenum, but my origional design would be hard as such. what kind of length alterations make a big difference? thanks.

[Sandy 189]

I would aim to use around 350-370mm from valve to mouth if you can design the manifold to accommodate it.

[brianthemagical 1]

thanks very much for the help sandy. i've found info on the theory behind ram charging, but no formlaes, and as you stated in batfink's thread, it's probs not easy to calculate. i was thinking along the lines of cutting the plenum off the std inlet, leaving the injector gubbins and mod the rest to accept ali pipes, pointing down from cut, to then attach the bodies. thanks.

 

i've just measured the inlet and i think it might be a bit long, or just long enough, leaving little room to experiment with the trumpets. oh well i s'pose.

on another note, is it possible to exploit pulse tuning with itb's, using the airbox as the resonant chamber? or am i fantasising. thanks agian.

Edited November 19, 2007 by brianthemagical

[ifcho 0]

Brian, pretty much what I'm intending to do.

 

Post pics here if you make them, I'll do some when I begin to do this as well, hope we can get that sorted

 

Regarding ram air - with the speeds achiavable with our cars I don't think there will be any gains and if there are, ram induction is much more complex, as you need to adapt the engine to the speed your car is travelling and back again, when cornering the air changes its direction, so the power will be down again if you depend on this.

 

I think TBs with well calculated airbox should be much better, than just leaving TBs out there with some sponges on them, but with the limited space under our bonnets fitting a proper airbox may be a little tough. You may find this reading interesting:

http://upetd.up.ac.za/thesis/available/etd-01242006-123639/

It's based on the inlet of a toyota works car, but basics would be the same for our engines as well: http://upetd.up.ac.za/thesis/available/etd-01242006-123639/

[brianthemagical 1]

by ram charging i was refering to the inertial ramming of the incoming charge in the induction system. i also think the air velocity hiting the front of the vehicle would be the same regardless of direction.

i've tried to do a little planning but i didn't have enough time to take anything off the car for a proper look but the alternator will get in the way and cause major trouble unless the tract length is huge, orthere may be a possibility of bringing the bodies forward, infront of the alternator.

i was planning on having an airbox with cold air feed and filter on the end, mainly due to cost.

[Sandy 189]

I'm not keen on airboxes generally, but to avoid loosing the independent breathing advantage of TBs, I think the volume should be as large as possible.

 

Experiment!

[brianthemagical 1]

thanks for all the help sandy. i've got access to an RR at uni, so experiment it is.

Edited November 20, 2007 by brianthemagical

[ifcho 0]

Hi again,

 

I am about to be making a manifold for the bodies, but I'm still not convinced which head to use.

 

I have two xu9 heads with the large valves,etc, and I have someone to make me an manifold. However I'm worried about the fact that the ports are rectangular, and the bodies are round...

Should I try to take some material off the ports and make them more rounder, or I should just leave them as they are and try to make the transition to rectangular ports inside the manifold?

Or should I just get a XU10j2 head which has round ports from standard?

Edited February 2, 2008 by ifcho