Throttle Upgrade – LS2 (90mm)
GM 90mm Throttle (Electronic Throttle)
Part# 12570790
custombuiltmotors
on EBAY
Purpose: Higher Flow into motor, more power.
Time: 2 hours
Price: $249.99 US
Shipping: 29.99US
– USPS
Duty: none
Brokerage: 5.00
Can
GST: 13.40 Can
TOTAL: $347.20 CAN
Contact: Chris
Let’s first look at the STOCK throttle on these cars.
78mm Electronic Throttle, with coolant passage.
Stock TB Flow @ 10" 529cfm Stock TB Flow @ 28" 885cfm
The idea here is to remove this throttle entirely, replace with the LS2 90mm throttle, which we take and port even further, putting us well over 1200 cfm. A ported 78mm gave 947cfm @28”…
A stock 90mm is approx 1170cfm.
To do a LS2 swap, a few things must take place. The LS6 (ls1 computer on the 05) uses a 6 pin (in one row) computer connector with position sensor connector while the LS2 throttle uses 3x3 in two rows all in one connector. A harness is required. One could be built, and ‘how to’ is further down the document, but I’m lazy this round, so I just bought one. Please refer to the 90mmThrottle_LS6_Ls2_Wire_adaptor folder.
The other must take place is the intake, what a time to pick
up, at cost, from Performance plus a 92mm F.A.S.T. Intake for 822 bucks
including tax. Yep Canadian. Ahh. Then the dumb-ass gets
fired; now I have to look elsewhere.
799.99 at texas speed free ship in the
http://www.pm-fl.com
. So time to do the old Adam connection;
ship to
Also to note, may as well do the PVC delete. This prevents the intake from ‘slurping’ oil from the valve case. Plug the intake side, and put a tiny filter on the valve as a breather now.
Intake: FAST_92Intake_wPVC_Delete. We also need to re-route the coolant line also known as the throttle body coolant bypass by LS1 people.
Both have a 4” lip… so intake plumbing will be the same.
Enough chat; let’s get to work on this throttle.
Stock ridges must go (yellow)
The red line is where the flap moves to completely close, this MUST NOT be altered as it controls idle. We opened Inlet side as there was enough aluminum to work with to make a direct ‘in’. Did not open the outlet side, just removed ridges.
Porting away
Polishing is so much fun!
Not bad… ridges gone; no interference with where the flap closes completely.
You can see some light marking on the flap and flap shaft, these are cosmetic blemishes only.
Off to get a manicure.
We decided to not flatten the shaft and/or thin the blade, as that requires disassembly of this nice throttle and is it really worth those extra CFMs? Isn’t 1200+ enough already?
Let’s install this bad boy.
We need to re-route the coolant that currently went through the old throttle, you know, in case of them cold days, you want the air warmer (roll the eyes).
***TUNING REQUIRED
- On an ETC car, this can be adjusted using the Idle ETC Area
Scalar from the stock value of 0.0255 to 0.0191 for the 2005 ls6 version.
End