Boost drop with headers

Has anyone measured boost drop before and after long tubes installation? I want to pulley down to maintain the current boost of 18psi, just dont know if I should add 1 or 2 lbs back in. I've searched and can't find any answers.

Setup is 2.65 gen3 TVS
Dragon tb
3.3 upper only
ARH 1 3/4 LTH 3in x pipe
Borla catback

Made 630rwhp on 93 at 18.5 psi
Yes I know boost is a measure of restriction etc....

Everyone is different. I had a setup that dropped zero, I have had a setup that dropped, 1.5# and one that dropped 2#. With exhaust that big I would think you are on the 2# side.

No reason why you can't/shouldn't add 2 lbs. with a smaller upper. If it was mine, I'd probably leave it as is with the LTs, unless I was looking to grab a few more ponies. 630 on 93 octane is very decent.

Thanks for the replies! Another question for you guys. Should I add the 2# in form of a smaller upper or a 2lb lower?

I already have a metco lower hub. The price for a lower and upper is the same price.

Also this was on a very stingy mustang dyno, I wonder what it would make on a dyno jet.

At that point I prefer lower at that point do to extra belt wrap. I made way more on a mustang dyno than a dyno jet so don't expect to necessarily make more .

Good point. I'll get a 2lb lower ring coming. Do you know of any metco discount codes?

My car had no drop in boost after installing headers.

--Joe

I would install the headers first then decide on the pulley, if needed, from there.

Good advice I'll probably wait to order it then measure before and after

I would keep in mind blower rpm is creating the airflow into the motor and power output. That won't change with headers so I wouldn't chase a boost number. If its 18psi prior to headers and you drop down to 17psi I would just enjoy the less restrictive setup.

Your blower is still doing the same work it was before

04torchred said:

I would keep in mind blower rpm is creating the airflow into the motor and power output. That won't change with headers so I wouldn't chase a boost number. If its 18psi prior to headers and you drop down to 17psi I would just enjoy the less restrictive setup.

Your blower is still doing the same work it was before

Click to expand...

You mean cfm means more than boost pressure?....
Air flow in is the key. Restrictions are just that, restrictions. Open up the exhaust and see how she likes it.

My boost dropped 1 psi after installing headers.

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