OTR or standard airbox with Magnuson mp1900 LS1

[gc83]

Hi
Im looking to purchase a Magnuson Mp1900 for a 5.7L LS1. The supercharger kit comes with the air box and components etc however wanted to find out from the experts if a custom OTR would be of benefit and if so by how much?
I currently have stage 3 ported heads, stage 2 cam, 3.9's and the OTR and like the response of the OTR. Would the standard box that comes with the s/charger kit affect the car whilst driving at low speeds (i.e. will engine suffer due to cam/ported heads and removal of OTR?)
Cheers

[Micks]

Minimal I think in a FI application, talk to your tuner but would lean to set it up with the supplied airbox initially. Especially so if you are looking at having it engineered approved for normal road comprehensive insurance. ;)

[aussiebbq]

Minimal I think in a FI application, talk to your tuner but would lean to set it up with the supplied airbox initially. Especially so if you are looking at having it engineered approved for normal road comprehensive insurance. ;)

Exactly this.

[white lie]

I've got a DuSpeed OTR on mine, think it's one of the only ones that will fit with the offset throttle body on the blower. Looks great but does strangle it above 500rwhp. That's purely due to the small filter size. Doesn't bother me as it it's enough power on the street and I race without the filter anyway. A large sealed pod will yield the best results.

The actual kit doesn't include an airbox, just the piping to the stock box. Unless you are buying second hand and they've thrown one in.

http://i235.photobucket.com/albums/ee264/mr_zogg/2012-09-07152447.jpg

[aussiebbq]

That offset intake makes my OCD kick in.

[white lie]

That offset intake makes my OCD kick in.

It's probably more noticeable when mentioned, a lot of people don't pick up that it's off centre, especially when running piping back to the stock air box location....It's just a necessity with the placement of the jack shaft on the side. I think the Harrops are centred as they run the shaft underneath.

[gc83]

Thanks for the comments people, its much appreciated. My car will be mainly a daily driver so I don't intend to do much track/drag.
Having said this, I think the magnuson 1900 comes factory with 6psi. I don't plan on doing any bottom end work and plan on keeping the car long term. Any suggestions of increasing the boost with a different pulley to around 8psi (or the safest you guys can recommend?). If so, what are your experiences of increasing it from 6, 8 or 10 psi?
This might sound like a novice question but I would like to make sure I get all the parts and do it right the first time.
Many thanks

[white lie]

Personal experience was this....
6psi made 450rwhp. Very lack lustre after the initial day of picking it up for the dollar outlay. Went back within a week with a smaller pulley.
9psi - 475rwhp. Much stronger, not a huge difference right up top but made a lot more torque as it's got that full boost the whole way thru the rev range. Was a completely different car.
A few more tweaks and pulling the air filter then made 520rwhp. Good enough for 11.2 in my 2T barge. Will run a 10 in a lighter car.

I don't think you'll be able to fine tune it to within 1psi. Just get the smaller pulley (3" from memory) and go from there. It may make 8, 9 or 10psi depending on your compression, the ported heads, cam etc.