Install trumpet inside plenum. Any difference???

[j_l200s]

according to wiki :

A velocity stack is a trumpet-shaped device which is added on to the air entry of an engine's fuel system, carburetor or fuel injection. It is designed to:

Allow smooth and even entry of air into the intake duct with the flow stream adhering to the pipe walls.

Modify the dynamic tuning range of the intake tract slightly by functioning as a small reverse megaphone which can extend the duration of pulses within the tract.

Alter the dynamic tuning speed if it includes extra length thereby changing the tuned length to a lower rpm.

 

[Dayline668]

So the short one got better torque or long one got better torque?

Longer will produce better torque then short.

---------- Post added at 06:26 PM ---------- 6 hour anti-bump limit - Previous post was at 06:15 PM ----------

according to wiki :

A velocity stack is a trumpet-shaped device which is added on to the air entry of an engine's fuel system, carburetor or fuel injection. It is designed to:

Allow smooth and even entry of air into the intake duct with the flow stream adhering to the pipe walls.

Modify the dynamic tuning range of the intake tract slightly by functioning as a small reverse megaphone which can extend the duration of pulses within the tract.

Alter the dynamic tuning speed if it includes extra length thereby changing the tuned length to a lower rpm.

Sorry for my bad english.. but i dun know wat it mean..?

 

[pcmoddingmy]

IIRC, longer trumpet will improve low-end torque... shorter trumpet for high-end torque, or is it the other way around. The best way is to dyno test it out...

 

[ajik8953]

Thanks a lot! will do it tomorrow...
the flange will make it at friend shop..

cikgu..how's it done?share ur pic la...

want to order 1 set for my use..boleh ka...hehe

 

[tofu_manic]

longer velocity stacks aid in lower-end torque, like what dayline sed

with/without trumpets, without it the air entry will be rough/messy, with it, response definitely improved, and seemed more eager to get off the line as well, just felt better all round

dcoe40/4g15 user here but applicable here as well haha

 

[Dayline668]

longer velocity stacks aid in lower-end torque, like what dayline sed

with/without trumpets, without it the air entry will be rough/messy, with it, response definitely improved, and seemed more eager to get off the line as well, just felt better all round

dcoe40/4g15 user here but applicable here as well haha

Weber user le.. come share ur setting..

 

[tofu_manic]

chokes = 32mm
main jets = 135
air correctors = 180

those are the specs if i remember them correctly haha

4g15 stroked to 1.6l, 272 cam, cdi ignition and other misc. stuff

 

[levin818]

I have plug in a set of trumpet in my ride last week. Its black in colour, no brand, length is similar to IMEC's (~1"). The result:
1) low end torque, from 3000rpm-5000rpm, was reduce a little bit, but not so significant if you pull from stand still. However, if you were at 3000rpm at 3rd gear and suddenly floor the fuel due to demand, you will notice the drop in torque.
2) Engine started to pull "a little bit" from 5000rpm till 7900rpm, linearly.

My ride set up - BT engine (balance) & 4-throttle, SVT wiring and ECU.
Perhaps if you compliment the set up with piggy back ECU, the feel will be more steam up

 

[Dayline668]

chokes = 32mm
main jets = 135
air correctors = 180

those are the specs if i remember them correctly haha

4g15 stroked to 1.6l, 272 cam, cdi ignition and other misc. stuff

Ever dyno..? how many hp gain..?

 

[tofu_manic]

I have plug in a set of trumpet in my ride last week. Its black in colour, no brand, length is similar to IMEC's (~1"). The result:
1) low end torque, from 3000rpm-5000rpm, was reduce a little bit, but not so significant if you pull from stand still. However, if you were at 3000rpm at 3rd gear and suddenly floor the fuel due to demand, you will notice the drop in torque.
2) Engine started to pull "a little bit" from 5000rpm till 7900rpm, linearly.

My ride set up - BT engine (balance) & 4-throttle, SVT wiring and ECU.
Perhaps if you compliment the set up with piggy back ECU, the feel will be more steam up

not 'perhaps' but 'confirm' the feel will be more steam hehe

Ever dyno..? how many hp gain..?

nope never dyno b4, but hp tarak byk lah sohc 4g15 onli hehe

 

[Dayline668]

dun say 4g15 only, datsun A15 stroked 1.7 weber can chunk out 200hp le...

 

[tofu_manic]

wow 1.7l with 200 hp, sohc isnt it? im guessing that is an all-out race engine with massive duration/lift cams

mine is more of a streeter, not bad low and mid but kinda breathless up top

oh well...getting kinda off topic here LoL

tenks for the a15 200hp info, didnt noe that, pretty impressive

 

[muzhaffar]

if we put the trumpet inside the plenum, the air stream will be distributed evenly or not?
because the air will enter from one side and all the trumpet will face the plenum..
logically, at high engine speed where air inertia is high, the last plenum will get higher air flow rate compare the first one..
but the injector is tuned to supply same amount of fuel for all 4 cylinder. however, because the air supply is not even, the a/f ratio will nat same for each cylinder.perhaps there will be one or more cylinder that will running lean.just like what happen of earlier version of 3s-gte engine based on what i read on wiki..
dont know either it is true or not..
just my opinion..
my concern is that does it will give side effect if we put trumpet inside plenum?

 

[tofu_manic]

to be honest, custom-ing an intake plenum is quite risky work...have to think about plenum volume / shape / trumpet size / length / distance from plenum wall / airflow@ X rpm / etc. etc.
ie. things i totally am clueless about

 

[pcmoddingmy]

Bro muzhaffar, stock setup already got trumpet, but the shape is like elephant trunk to reduce the induction roar and is made of plastic(or rubber). So I believe there shouldn't be any issue installing trumpets inside the plenum, unless it is longer than 2". Besides, I understand that air doesn't travel in one direction and the plenum is designed to pull air from the bottom portion. So logically it shouldn't be any problem. Besides, you can test it out yourself by cleaning the plugs and checking each plugs individually after a few runs with the trumpets. If all of them are in similar color, then the airfuel mixture should be similar on all cylinder.