New LS2 intake and 90mm Nick Williams TB for the 408

[NITROUS]

I'm going to buy it and put it away because I won't need it with the supercharger. I've just read so many bad things about the LS2 intake compared to the LS6 and LSX intakes. Allen, you probably have experience with them, what's your take on them?

[RedHeartbeat]

On a 5.7, nope. A LS6 intake will help more. On a 408, maybe. I'm only doing the LS2 as a stepping stone to the 90mm TB. The 78mm TB is choking my 408. I'm hoping it adds about 20HP having the extra air coming through. $230 is cheap. I paid $450 shipped for the intake, injectors, fuel rails, TB and MAP sensor. I couldn't turn down the price. Basically I got a brand new NW TB and a free intake, injectors and MAP sensor.

[farmtruc]

Allen, you probably have experience with them, what's your take on them?

Going from what Red is saying and based on his situation, ya, I'd say go for any those intakes, mainly to do a 90mm, that's the big jump for him.

I'm not letting too much out of the bag, but we'll have some good results for you very soon. We have a dyno engine we're testing all the parts on.

[RedHeartbeat]

Got the conversion done. It went too easy.

Be sure you wash the top of the engine down good before removing the intake. Use degreaser or engine cleaner and a low pressure hose to flush it off. High pressure can bypass the silicone seals and get water where its not supposed to be.

Remove air cleaner attachment at the throttle body
Remove idle air control connecter
Remove throttle position sensor
Remove the fuel rail/coil covers
Disconnect the coil pack main connectors (2 - one on each side)
Disconnect the fuel injector connectors (8)
Disconnect the manifold air pressure sensor
Remove the brake vacuum boost hose
Relieve fuel pressure at the schraeder valve, use a catch can or rag to soak up the fuel it releases.
Remove the fuel lines from the fuel rail using a fuel line tool. Have rags under the line to catch the fuel. Cap the fitting so gas doesn't get on everything while you're working on the manifold.
Remove the Evap connection at the manifold
Remove the EGR hose connect at the manifold and remove the hose assembly
Remove the (10) 8mm headed bolts that holds the manifold to the engine
Remove manifold and move to a suitable work table
Remove the four bolts that retain the fuel rail to the manifold and seperate the fuel rail and injectors from the intake
Remove the injectors using a flat blade screwdriver to remove the circlips holding the top end of the injector to the fuel rail and then pull the injector from the rail.

Clean all parts you want to transfer to the LS2 intake.

If you're going to be using LS1/LS6 style injectors, you'll need to order the KAT-A4096 (Katech from SDPARTS.COM) mod kit with bolts, spacers and seals for the lower end of the injector since the LS2 has a larger bore that the injectors sit in.

An LS2 coolant crossover hose for the front of the engine would be advised or you'll be bending and tweaking yours by hand like I did to get the front of the intake to sit flat when you try to install it.

Check your LS2 intake and make sure the seals are installed on the intake ports and throttle body seal.

Install the manifold air pressure sensor in the hole at the front of the intake behind the throttle body.

Install the manifold onto the engine. The bolts from an LS1 or LS6 are the same as the LS2 bolts. Place the fuel rail stop on the manifold from the original setup, drivers side rear. Tighten all intake bolts to spec 44 inch pounds first round and to a final spec of 89 inch pounds. Yes, inch not foot. Don't PM me telling me you took your two foot long torque wrench and twisted the 4mm bolts off trying to tighten them to 89 foot pounds.

Install the new lower seals on the injectors. Put the injector retainer clip on the injector with the open end facing the wire connector, then snap the injector onto the LS2 fuel rail.

Install the fuel rail onto the intake manifold, carefully align all the injectors into their bores before pushing it all the way in. Place the aluminum spacers between the LS2 fuel rail and the intake, add the bolt and snug them down to 89 inch pounds.

Connect coil pack connector, fuel injector connectors, add a new manifold air pressure sensor extension (KAT-4751 Katech) from the sensor to the original connector. Reconnect the fuel line to the fuel rail.

Install the new throttle body. You can use the three bolts from the original TB but you'll need a fourth.

Remove the idle air control valve and throttle position sensor from the original TB using a #20 torx bit. Re-install the sensors into the new TB.

Connect the IAC and TPS to the wiring harness.

If you're using a cable type TB you'll have to build or buy a mount for the throttle cable. I reused the original LS1 Camaro throttle cable bracket and cut it down to fit. I cut the material off the side that mounted to the LS1 intake and then cut a piece of angle iron to weld it to. The piece of the original cable mount was slid under the MAP sensor and lifted up as high as it would go and then it got tacked to the angle iron. The angle iron has two holes drilled in it to bolt in place at the passenger front end of the manifold retaining bolts.

Install the EGR assembly and hoses. Install the brake booster hose. Cap off the small hose next to the brake booster hose on the back if the intake if you don't have anything hooked to it.

Install the air intake tube.

Replace fuel rail covers. NOTE: stock LS1 covers will not fit without major modification. Get a set of LS2 covers or get used to a naked engine.

I'll try to take some pictures of it tomorrow in the daylight.

I hope I didn't miss anything.

Now to work on updating the tune.

[NITROUS]

Sweet! Let me know how things work out and show us some pics. You'll probably just need to increase the MAF table for compensation.

[RedHeartbeat]

I had an issue with the truck starting after the conversion. Here's what I found out. The MAP extension harness was wired wrong. I had to repin the connector. It fired right up once I had that fixed.

[SCIV]

Well, test run opinions? Need a new tune to compensate for the added air? Running lean?

[phantom405]

so whats the difference in this intake the and the fast 90/90? looks like you could grab basically the same gains?

[RedHeartbeat]

The FAST 90/90 has better flow characteristics and I believe it was designed specifically for the flow characteristics of the 5.7L engine. I've seen numerous dyno results showing the LS2 vs LS6 intake on 5.7s and the LS6 beats the pants off the LS2 intake, the FAST improves the numbers by about 8HP over the LS6. Of course they're comparing 78mm setups to 90mm setups. I've not seen the same comparison on a 6.7L/408 like my setup, though. These engines require a lot more air. Even GM realized it and put a 90mm TB on the 6.0 engine. I'm thinking a larger TB is in order for the 6.7/408 than even a 90mm. It would be nice if someone would donate dyno time and a larger TB for testing.

[RedHeartbeat]

well, truck runs good but tuning will be necessary. I fattened up the volume efficiency table +10% but had other issues. One of the S&P idle pulleys broke off and tossed the belt, also lost the pulley. The threads pulled out of the aluminum. Another issue is the transmission is starting to slip going into 2nd gear. I thought these 80e transmissions could hold some power?