MR2 Owners Club Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
29 Posts
Discussion Starter · #1 ·
Probably getting ahead of myself here since the car has other problems, but right now my Blacktop has a cheap autozone spectre intake. Around 2-3k rpms, it sounds quite bad. I am looking into installing the 100mm trumpets. How hard is this to do? Can I just take the autozone intake off and bolt the trumpets on? Do I have to mess with the fuel system? Is there a write up or video on how to do it, I can't find anything except stuff like this
which doesn't show the install of the trumpets from before unfortunately.
 

·
Registered
Joined
·
185 Posts
Not if its running a BT loom and map. I dont know what the intake you have looks like but if it runs through an AFM to get to the throttles, you wont be able to go open throttle.
 

·
Registered
Joined
·
1,432 Posts
Respectively suggest you do some research on "resonance supercharging" as well as understand that if you install the wrong size velocity stacks you may be back at the problem your attempting to fix, or worse.

Just slapping on velocity stacks with no knowledge of the physics involved is like street punks installing coil overs. A joke at best.
 

·
Premium Member
Joined
·
12,211 Posts
Respectively suggest you do some research on "resonance supercharging" as well as understand that if you install the wrong size velocity stacks you may be back at the problem your attempting to fix, or worse...
In short:

... resonant induction is a half cycle of a quarter wave resonator. The resonator is the combined cylinder and intake runner, with the piston forming the closed end and the plenum junction forming the open end. The effective length can be estimated as the total length you would have if the intake runner was extended by the cylinder volume. Doing the math, if the cylinder volume is v and the runner has volume V and length L, then the effective length L_eff = L (v + V)/V. In a quarter wave resonator at resonance, there is a pressure peak at the closed end and a flow peak at the open end, which is exactly the case desired for induction. Note that the length of the intake runner by itself is irrelevant, since the runner has two open ends, which do not meet the needs of induction. A half cycle is the interval from minimum pressure to maximum pressure at the piston, and when the half cycle time roughly matches the time from TDC to BDC, resonance occurs and induction is optimized, usually with a modest supercharge..
 

·
Registered
Joined
·
185 Posts
Originally Posted by rmeller View Post
... resonant induction is a half cycle of a quarter wave resonator. The resonator is the combined cylinder and intake runner, with the piston forming the closed end and the plenum junction forming the open end. The effective length can be estimated as the total length you would have if the intake runner was extended by the cylinder volume. Doing the math, if the cylinder volume is v and the runner has volume V and length L, then the effective length L_eff = L (v + V)/V. In a quarter wave resonator at resonance, there is a pressure peak at the closed end and a flow peak at the open end, which is exactly the case desired for induction. Note that the length of the intake runner by itself is irrelevant, since the runner has two open ends, which do not meet the needs of induction. A half cycle is the interval from minimum pressure to maximum pressure at the piston, and when the half cycle time roughly matches the time from TDC to BDC, resonance occurs and induction is optimized, usually with a modest supercharge..
Sweet lordy Jesus, i lost the will to live half way through reading that.

You could do something ridiculous like actually test some trumpets in the real world...
 

·
Premium Member
Joined
·
12,211 Posts
Sweet lordy Jesus, i lost the will to live half way through reading that.

You could do something ridiculous like actually test some trumpets in the real world...
I am glad that you survived. I wouldn't want your demise on my hands.

I approve of that too. However, engineering moves ahead with accurate science, and physics doesn't need to be scary or boring.
 
1 - 8 of 8 Posts
Top