[Rich-Tripower]

Plastics (intake system, intake manifold) are poor conductors of heat. But consequentially, they also let go of the heat they do gather more slowly. So, the goal is to try to keep them away from as much direct heat as possible. And yet, this is all a "any little bit helps" kind of thing. I already know my intake air (at the intake point) is just a little above ambient when the car is fully warm and moving. Much different when sitting still but it does drop very quickly again once motion is established. And as far as air flow goes, I do know the hood scoops do allow air to pass through as evidenced from when I had a Vararam and how the VR filter got dirtier quicker where the hood scoop openings were. Not a real stretch of the imagination to see that air from the scoops goes in at the front top of the engine and then out through the lower rear of the engine compartment. It is certainly not like the air just hangs there and heats up once the car is in motion. There is also air coming in from under the leading edge of the hood. It has to go somewhere as well, ie; back, down and out.

In my set up I have ceramic coated headers. I was greatly surprised how much heat they prevent from going into the engine compartment in the first place. A good coating does a lot more than you'd think. I also insulated my DuSpeed on the underside to keep it as free from contact or radiant heat from the radiator as I could. I could only do so much as you really can't squeeze much material in inbetween the intake and the top of the radiator. Additionally, I'll add my homemade under intake manifold heat shield. Will it help? Will it make any noticeable difference? Doubtful. It certainly won't add 20hp like the readymade one is claimed to. But I can't see how it would hurt.

But, in the end, hot rodding is all about trying things and often times about gaining performance by doing a myriad of little things that all work together. It's not ALWAYS about throwing cubic money at a car to make it go faster or handle better. If my heatshield helps, great. If it doesn't, I'm out next to nothing dollar-wise and a couple of hours wrenching on my car which I enjoy doing regardless of the reason. Trying to learn a little something along the way is a bonus.

 

[Nothubertjfarnsworth]

But, in the end, hot rodding is all about trying things and often times about gaining performance by doing a myriad of little things that all work together. It's not ALWAYS about throwing cubic money at a car to make it go faster or handle better. If my heatshield helps, great. If it doesn't, I'm out next to nothing dollar-wise and a couple of hours wrenching on my car which I enjoy doing regardless of the reason. Trying to learn a little something along the way is a bonus.

:mswerd:

 

[Kfxguy]

heat energy is coming from multiple areas in the engine bay. as discussed before, we have radiative, conductive, and convective. the engine, radiator, and exhaust manifolds are the primary contributors.

of the three types, i would bet conductive is probably the greatest contributor.

only the top of the plenum is exposed to air that has been heated by the radiator/exhaust... the rest of the external surface area is presented to the heads and engine valley cover. it actually touches the heads, and not the valley cover, but it is pretty close...

with the car in motion, air is exhanged out of the engine bay through the bottom, and possibly out of the top (through hood scoops and PERHAPS the cowl area if it isn't sealed with weatherstripping, although the cowl area is technically a higher pressure area and might not contribute to engine bay airflow...) i would worry more about heat soaking the intake manifold from air convection while the engine sitting rather than with it in motion.

anyhow, as i said, this is an "every little bit helps" mod.

my bet is that insulating the bottom of the intake helps to stall heatsoaking, which is better than nothing. i have experimented with reflective materials on intake tracts on other vehicles, and in my experience, intakes still get heatsoaked, but it does take longer. it works, but it isn't magic--laws of thermodynamics still apply here.

add in other tricks to draw air from as close to ambient as possible, increase engine bay airflow, decrease air exit temp out of the radiator (lower temp thermostats, although you really don't want to go below 170-180 degrees), insulating the intake tract, insulating the exhaust manifolds/headers with coatings and wrap, etc... and you arrive at a better overall picture of a system that allows for cooler intake air temps.

i wouldn't spend 60 bucks on a small peice of reflective material, but the idea is sound. i just wouldn't buy into any idea that it works wonders and adds 20 horsepower.

Well said

 

[Kfxguy]

Posted this on another ls based forum but anyways



So I got around to installing the dorman 615-901 intake after work yesterday. Didn't really take too long although I had some issues. I'll elaborate. 04 ls1 gto btw

First, there's a vacuum port on the rear of my ls6 intake that this one was lacking. I noticed there was a torx screw in the general vicinity that was sealed with sealed. I removed it and it went into the intake. Good, perfect spot for a fitting. Of course the auto parts store doesn't have a fitting with the small thread I needed so I machined a stainless nipple (ac vacuum hose is what goes here) and threaded it with a 10/24 die and tapped the intake for that. Voila. Instant vacuum port.

Next, so I set the intake on the motor for mockup. Well the map sensor wire didn't reach. Cut some tape off the harness to free up slack. No problem. The coolant crossover tube in the front sits up a touch too high. I was able to bend it down just a touch by hand and it cleared. Maybe this is why some people cracked intakes when putting them on for the first time. I could see that being an issue if left unnoticed.

The brake vacuum hose went on good. No issues there. The evap port on the front driver side by the throttle body was angled the wrong way (probably just gto related) because it was aimed at my power steering reservoir bracket. Slotted the homes, turned it a little.

Bolted throttle body on, wouldn't open. Damn. 92mm throttle body, looked like in preliminary checking that it ha clearance. Nope. I'm already done and at this point I'm not taking the damn thing back off. Out come the die grinder and a vacuum. Very carefully clearances it while vacuuming chips and dust. I know, the horror right? Well at least it's not aluminum! I kept it clean so I'm not worried about it. Time for a test drive. Of course my shift points and lockup are out of whack now. Engine fired right up like nothing ever happened. Made a few throttle adjustments to get my iac counts right and it's purring like normal. Back to the shifting. Yea it's shifting out early. Made some adjustments on hp tuners and got it better. When I got home I opened up the trans tool utility I downloaded and revamped the whole table for the bigger throttle body. After doing a few logs I noticed I'm only getting 80% throttle. I noticed that also when putting it together. Not sure what's up with that but I'll have to figure that out tonight. I can't comment on the power difference because the roads were wet last night. Supposed to rain all week so it may be a few days before I can get on it.

 

[11chuck]

I would do a visual inspection to see if it's actually opening all the way. The 80~% reading has happened to me before on my LS2 even though it was fully opening, has to do with the way it's being read I believe.

I grew up in Denham btw. Don't make it there much these days, but when I do I let the goat loose on 4H.

 

[Silvah Goat]

If you have the TPS positioned right and it has been zero'd, then most likely the springs on the new throttle body are too strong and the traction control servo is taking up the rest of the pedal travel. I had to remove 1 spring of the 2 to reduce how much tension was on the blades. It's also possible the cable throw is incorrect if the new throttle body cam is a different in size. The size of my throttle body cam wasn't the issue, but each situation is different. You can check it though, just look to see when the traction control motor starts picking up the slack.

 

[Kfxguy]

Sorry guys I haven't updated. So first I thought the springs were too stiff because I noticed that when the throttle stopped moving, the pedal still had travel and would continue to move. Took the cover off the traction control unit, verified that's what it was doing. So I robbed a spring off an old 5.3 throttle body. Nope. Same stiffness. Damn. Then I noticed the way the spring was clocked that it was wounhalf a rotation tighter. After some milling and drilling, I made a new location for the spring. Throttle easy now. Way too easy. Driving the car was jerky. Got full throttle though (that wasn't the issue however) so then I decided to put the doings back in that came with the throttle body, knowing they are the same tension, I had to do something about how easy it was to press. I decided clock one spring (there's two springs for those that don't know) to the tighter position and one to the looser. Perfect! Feels like stock. Throttle doesn't hang anymore (that was an issue too at idle) but now I'm not getting full throttle again. Wtf? Then my son noticed that a part on the throttle cam on the throttle body was hitting a nub on the intake. So why did I get full throttle before? Well there's a set screw on the throttle cam and it was moved further out on the shaft in one of the times I assembled it. Damn. So that's squared away. On to what I think of the manifold.


I don't have it dialed in air fuel ratio wise as good yet as I had the stock intake. I'm still working on that but it's been raining here almost every day so I haven't finished. Right off idle, a full throttle stomp doesn't result in 2-3ft of tire spin like I usually get (I'm on drag radials) but it just hooks and goes. So that tells my the right off idle tq is down. Could be tuning. But midrange and top end is noticeably stronger. A 45mph roll (rolling along at 45, punch it, down shift and go) is definitely stronger. Before it was laughable at that speed, it didn't start pulling till 55-60 so I would normally punch it at those speeds because it was so weak feeling slower than that. The top end is noticeably stronger like I said but not as much difference as the midrange and it's running richer in the midrange than top end righ now so there's room for improvement.

 

[stickpony]

Exactly. From what is widely known about the ls2 intake is it has internal leaks that cause issues and a lot of stuff don't line up on the inside that you can't get to. I have no personal experience with this intake but that's lots of hate for it on the web. The dorman should be a good bit better but I'm a little concerned if it's going to pick up power over my ls6 intake. We all know the ls6 is a good intake and can be better with a bigger throttle body hole and bigger throttle body. Supposedly the lsd2 intake is supposed to be the best of both worlds but from what I've seen it needs a little cleaning up out the box. I really need to order my stall so I can put my cam in but I'm very tempted to order the dorman and try it and sell my ls6 if I seen a gain. Plus I could do an intake swap much quicker than a stall and a cam. But a stall an cam are worth much more. Decisions decisions lol

not to mention is is cheap and ugly, not very OEM looking, and has lots of generic writing on the top

 

[MuhThugga]

If people can make the truck manifolds look good, then these Dorman units should be a piece of cake.

 

[Kfxguy]

Anyome else put one one? Dyno test? I may be selling mine soon. Thinking about an ls3 swap.

 

[Slightly.Above.Average]

Anyome else put one one? Dyno test? I may be selling mine soon. Thinking about an ls3 swap.

Nobody has done a direct intake swap and dyno test with the Dorman LS2.

Closest is a guy on corvetteforum.com, but he did a heads swap with it so, those results mean nothing for the Dorman LS2.

 

[Kfxguy]

Nobody has done a direct intake swap and dyno test with the Dorman LS2.

Closest is a guy on corvetteforum.com, but he did a heads swap with it so, those results mean nothing for the Dorman LS2.

Well poo. Just thought I’d ask

 

[Nothubertjfarnsworth]

Nobody has done a direct intake swap and dyno test with the Dorman LS2.

Closest is a guy on corvetteforum.com, but he did a heads swap with it so, those results mean nothing for the Dorman LS2.

i wasn't too impressed with dorman's ls1/ls6 manifold. it made 5 whp less on a dyno than the real deal, iirc. people claim that porting wakes it up... why the heck would i want to port a part that costs as much as what my car came with that already does the job? :gto_rage:

the ls2 version is basically the ls1/ls6 version with a 90mm throttle body flange. yay. it might barely equal the stock LS6 manifold now.

 

[Nothubertjfarnsworth]

sorry... let me tell you how i REALLY feel.

 

[Kfxguy]

i wasn't too impressed with dorman's ls1/ls6 manifold. it made 5 whp less on a dyno than the real deal, iirc. people claim that porting wakes it up... why the heck would i want to port a part that costs as much as what my car came with that already does the job? :gto_rage:

the ls2 version is basically the ls1/ls6 version with a 90mm throttle body flange. yay. it might barely equal the stock LS6 manifold now.

It was said on ls1 tech that the ls2 manifold is different and that it flows on par with a tbss intake which is supposed to be one of the best factory intakes to use. When I installed mine two things I noticed, a 45mph punch in 2nd seemed to have much better response and I was able to raise my limiter and shift points about 200rpm because it actually pulled higher than it did before. I’m pretty in tune with my car and how it feels, I could be wrong and maybe it didn’t pick up squat.....I hope I am but I really don’t think I am. If I were wrong then it would be worth doing a fast intake but I don’t think it’s worth the cost.

 

[Kfxguy]

sorry... let me tell you how i REALLY feel.

I’m all ears lol

 

[Slightly.Above.Average]

...the ls2 version is basically the ls1/ls6 version with a 90mm throttle body flange. yay. it might barely equal the stock LS6 manifold now.

I pretty much agree with ya. If you've done every other option and an intake / throttle body is your last bottle neck and you want to save money. Then the Dorman MIGHT be worth it.

In my opinion the Dorman will not be an improvement over a LS6 intake unless the engine is starving for air due to large cam, swapped heads, stroked, etc requiring more CFM than the 78mm throttlebody can provide.

 

[Nothubertjfarnsworth]

looking at the numbers i posted earlier in the thread, i suppose it's a good, economical option. i was just a bit put off by the hype and the utter let down when i actually got a hold of the physical manifold and examined it.

with the FAST 102 dropping in price, if you have the money, i would just get that.

 

[Nothubertjfarnsworth]

i just checked on a few websites and it's starting to get backordered. sheesh.

 

[MuhThugga]

Where is the 102 dropping in price? Everywhere I look, that thing is still $850.