NITROUS OXIDE ( nos / n2o ) advice forum

Trev:

I just received a 350 jet and it looked way different than a jet I bought three months ago, give us an explanation of the new design.

Trev is out of town and may not see this thread as soon as you like so I will answer.

Most U.K. cars don't run over 150hp regularly so the smaller bodied jets up to a 300 stamping were fine and then higher hp jets were just drilled out as you were aware of for custom applications. The past few years higher hp cars have been in higher demand of the products and drilling the smaller jets out were not the standards Highpower likes since the jet outlets could splinter as the bodies were being maxed out in diameter, so Highpower had all new bigger size bodies and machined jets made to accomodate the masses.

Denny:

you made an earlier comment that they flow more than the stated value, please explain

You'll have to speak to HP about this for specifics.

I'll send Ant the shop manager to this thread too clear this up.

Hi Jack,
The orignial Jets were/are designed to have a short parallel section. When they get drilled out beyond their original value the parallel section becomes the whole length of the jet which makes the jet more restrictive so you only get 90 - 95% of total flow.

The newer jets are desinged the same way but to allow an even greater overall flow capability they have an even shorter parallel section which has caused them to very slightly 'over flow'.

The problem isn't really that they flow more than they're supposed to (eg @ 200 bhp they might actually flow 206 bhp @ 950 psi - so not a big difference). The problem is the difference between the two. For example an old 400 jet might flow 186 bhp where a new 400 jet might flow 206 bhp. That's a 20 bhp difference which may cause a problem for a highly tuned system.

Bascially, if your changing from older style jets to the new larger style (This only applies to jets over 300 BTW) then be aware that you might need to up your fueling a little because your old jets were slightly 'under flowing'.