BT20v plenum vs TechnoToy tuning velocity stacks.

[sundee]

Here is a little article comparing a stock intake with open velocity stacks.

This particular comparison compares the OEM air box with Techno Toy Tuning 75mm billet full radius velocity stacks.

An increase of approx 8.3hp and 3.2nm torque.

The test is not at all 100% ideal, but gives you a rough idea of what to expect.



Discuss

[LittleRedSpirit]

I want to see the airbox tested with cold air feed and correctly formed 30mm trumpets inside before I get influenced either way. That said, if you could put TTT trumpets in a box youd be kicking ass I reckon.

[sundee]

yeah i agree with you totally.
i thought though, it is a rough look at what sort of effect Trumpets have over an airbox with stock tubes..
i did cringe when i saw the stock tubes butchered,

Factory airbox with TTT stacks and cold air intake would be a pretty good deal.

[LittleRedSpirit]

I think so, however this data doesnt really mean anything in a practical sense. Box or no box the stock trumpets would be far better performing if they were intact.

To accurately weigh up the benfits, you really need to dyno the best case scenario of each setup. So that would be the ttt stacks open in a pipercross filter foam enclosure, so that sock filters wouldnt knock a couple hp off the top.

Then pit this against something like a modified stock or noby booth style airbox with 30 or 40mm trumpets, whatever fits best spacially in rwd, and a cold air feed. Then you could accurately quantify the benfit of doing it the best version of each way. I think with fully formed trumpet mouths on each setup, the differences would be more about having a chamber to control and harvest intake resonance better, and the benefit of cooler denser air.

[sundee]

agree

[Sam-Q]

I don't know why they would of bother to write a whole article about a completely pointless comparison.

That said I would of liked to see the results of the uncut version as you guys have said. Even though an airbox helps I would be betting on the T3 stacks coming out in front. The original blacktop stacks are pretty bad.

[Matt]

SQ Engineering stacks are....

1. Cheaper
2. Flow better
3. Have warranty from a local provider.

No brainer there as to which ones to order...

I agree the article written may as well have just said "Apples taste better than oranges"

[Sam-Q]

well thanks but I think the better reason is that 75mm velocity stacks just about touch the brake booster and leave no room for a filter. That's why when I custom designed my billet ones I went for a 50mm length.

[dove grey 64]

Giving me dirty thoughts of a pair of stacks on my twin carb honda :/

[Matt]

So recently a Duncan Harrison did a heap of back to back dyno runs using PVC tubing on his car to get an indication of what the effects of the longer stacks are.



Sure these aren't permanent, but the results mirror what the experts have been saying for years. The longer stacks give you more power.



Test 1: 75mm
Test 2: 95mm
Test 3: 115mm
Test 4: 135mm

NB: At around 7500 rpm the pvc tubing was being dislodged from the throttles.

The other test shown in Grey is with filter socks and the red one is without. Though the price of an engine running a form of filter is always worth it.