CAI, do I really need one?

[99Yuk]

Danny_Z56, your right.
I recieved my K&N drop in replacement filter on Monday.
I like it.

Everything that he said, I noticed. Less on the throttle when accelerating, nicer pull on the hwy, etc.

I'm still torn on the big hole in the airbox (heat soak vs having lots of air available to it). To be honest I'm not thinking that 10-20 degree celcius higher temps are enough of a negative to offset the increased volume of air and the ease of which to obtain it available to the intake. By that I mean, sure higher temps are bad, ok, I get that. But I'll bet that more free flowing air is a good enough mod to offset the higher temps and still give a gain of sorts.

I think that I'm going to try 350Vortec's "Keep the stock air box but just change the ****** flex pipe out for a solid clean pipe." trick next. Then the ported TB. I wonder what kind/size of pipe he used? 350vortec, do you have pics to show us how you did it? Thanks. I'm thinking 3" black plastic abs with sewer clamps on each end?

 

[Danny_Z56]

The thing is,our stock airbox's are huge as it is lol.Every time i show someone my motor they are always like "wha look at that big a$$ airbox".Plus ontop of that we have a cone style airfilter.So all in all their is not a whole lot of air restriction with our stock airbox.

The rest of the air intake however....

 

[99Yuk]

The rest of the air intake however....

So to that end, I went googling. I found this.
Home-made-air-intake-for-96-99-Vortec-trucks
This morning I started buying the parts at HOME DEPOT. I'm going back tomorrow, I couldn't find the ceiling pipe clamp. I'll look again, maybe ask an Orange coat. This Mod just straighten outs the air flow at the filter. Might do something for me, who knows. I don't think that there is much difference in this vs. the spectre CAI, except maybe the slinky flex pipe that 350Vortec was trying to tell us about.
I'll let you all know what I think of this Mod.

So to recap based on data from the real-time scantool on steering column and seat of the pants feel;
- Remove top of air box, lots of cool sound, On idle ~10-20 degrees higher temp, same temp as stock when on Hwy. No real gains in performance or mpg.
- Replace stock filter with drop-in K&N, same sound, same temps, but better acceleration, too soon to tell MPG.
So the only thing that made a difference was the K&N drop in filter, and if you like noise, then cut a hole in the top of your air box leaving the backside as a heat shield as in the K&N and Volant CAI kits.

 

[Danny_Z56]

^ I think the Volant CAI system conceals the cone filter from any underhood heat.Unlike the K&N and Spectre CAI systems.The K&N and Spectre systems will give more sound and better airflow and im sure a few extra HP,however they will take in more heat,maybe not alot but more none the less.If they could just make their heat shields seal to the inner fender well and hood then they would be much better.They just seem to leave to many "gaps" for heat to get in.

This is just my opinion and not set in stone.I am not an expert in this area by any means.

 

[99Yuk]

I am no expert either, just a self-confessed geek who likes to experiment.

So here is an update.
Last Sun, I installed the $2.50 2" rubber Fernco cap over my silencer box.
Wow!
I think that I'm going nuts. I can feel the difference. I like it. The extra noise not so much. But the kick in the pants, I like. I would never have believed it, if I didn't do it myself.

Thing that I have noticed.
- With the AC off, I can spin out the rear end going around corners on dry pavement, previously I needed wet pavement to do that(I'm serious). Not from a standing start yet, but it's comming. I can almost feel the magic.
- I've been using a long upgrade hill with a set of lights at the bottom, that I travel on in my daily work commute as a guide to judge each mod. Even Monday while dragging around my trailer, I felt a difference, but after driving yesterday and this morning. Wow. I can go up that hill and gain speed in a higher gear with a lower rpm. Ie the truck is pulling much much harder now, without dropping a gear and reving up. Awesome for passing.
- Today is Wednesday, and I havn't visited a gas station yet this week. I typically consume a little over three full tanks a week. That being said, I'm down to 1/4 now, and I will have to fill by this afternoon, but my point is that I mssed my tuesday fillup.
- TPS% numbers. I thought I was going nuts, that a $2.50 mod could do this for me. So I'm looking for every damn excuse that would explain this. I'm really focusing on how far my foot is into the pedal by watching the TPS numbers as I drive. I swear they are lower to maintain the same cruising speeds. Maintaining 60kph(40mph), currently I can coast, or just feather the throttle, we are talking 10-15 TPS% feathering with a whole lot of coasting. I previously couldn't coast at that speed, and my foot was into it at about 15-20%.
- My truck has lost it's amneimic, slow, heavy feeling. It seems to rev/breath easier and faster. It feels awake.
- On WOT, I can feel the truck push me back into my seat. It's never done that before. A brand new GM crate motor with less than 40,000kms on it couldn't do that before.

So to recap, mods that have worked really well so far are the drop-in K&N filter, and the delete silencer box.

I'm hoping that by the end of the week, that I find a better explaination for why the truck is running better other than spending $2.50, because if I can't, I'm going to have to kick myself in the ass for not doing this sooner.

BTW, right now AC is making a difference between magical and not so much. I'm hoping that after I do the rest of the experiments, that I can run AC and still retain magical.

I'm not sure which will be my next experiment. I'm still missing parts for my air replacement duct. And I ordered Janzters ported TB based on readin FF40's feedback. It's going to be a toss-up to see which one gets installed first. This morning I went to a plumbing store, and asked for a ceiling mount, they brought out three different types of mounts, and not one of them is what I'm looking for. Sigh.... Maybe I'll have to buy from the I-net.

BTW, I found this EGR bypass kit. What is the downside to installing this other than requiring a tune to remove the EGR, I mean why is the EGR there in the first place, and do our engines run ok without an EGR? I think that's it's there just for fuel economy and/or emissions. well, living this far north, there are absolutely no emmisions checks that I have to worry about. None.

 

[Danny_Z56]

EGR is typically not employed at high loads because it would reduce peak power output. This is because it reduces the intake charge density. EGR is also omitted at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle. The EGR valve also cools the exhaust valves and makes them last far longer (a very important benefit under light cruise conditions).

In every one of my PCM reprograms,i always had the EGR tuned out.I never had an issue what so ever...

 

[99Yuk]

EGR is typically not employed at high loads because it would reduce peak power output. This is because it reduces the intake charge density. EGR is also omitted at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle. The EGR valve also cools the exhaust valves and makes them last far longer (a very important benefit under light cruise conditions).

In every one of my PCM reprograms,i always had the EGR tuned out.I never had an issue what so ever...

Perfect! That's what I was looking to hear. No ill effects other than a tune.

So here's an update on the deleting the silencer box.
After the euphoria has died down a bit, I really looked hard for an explanation as to why it feels so much better. Most of this week, I havn't had to turn on the AC, so I was getting the full effect of the mod.
As far as I can determine, I still like it.
I have been watching my TPS like a hawk to see how far I have my foot into it when accellerationg from red lights, and constant cruising.
I have found that the truck has lost it's slow, lethargic feeling, and feels lighter, faster. At those times while accellerating, my foot is into the TPS pretty hard. harder than before. But it's because the truck gets there so much faster than before. It revs up and gets going faster than stock, so while there is no magic HP gain, it does feel faster, probably because it is getting lots more air.

As for cruising, I'm really impressed. My foot is definitely into the throttle less than stock to maintain the same hwy speeds. Anywhere from 5-10% less. I think that's where my increase in MPG is comming from. It's not a dramatic increase, but it has shifted my weekly fillup patterns.

I can't wait for my bigger TB to arrive! Or for me to finish locating the parts to replace the slinky flex tube and straighten out the air flow.


I do have some preliminary conclusions though. The point of this experimenting was to determine how well does a CAI kit perform? Why is the $300 K&N better than the $60 Ebay kit?
Is heat soak really a bad thing?
And the answer seems to be that a $60kit will be just fine. Even DJtricky's homemade kit will work (and is working). The Idea of these kits is to increase the volume of air, while smoothing out the path of the air flow. The notion that you have to spend an extra $240 for a heat shield provided by K&N is not worth it, IMO. People are right, it sounds great to have no heat soak, and it probably is. But the price difference in the high-end kits vs the low-end kits is too high to compensate for any advantage gained by not having heat soak. IE not worth the money. Again no flames please, just my opinion.

Haha, it's funny, as I'm doing these experiments, my buddies are laughing at me, calling me a french redneck. Ok, fine... This week, the first buddy pulled the top of his airbox off, bought a K&N drop in filter and removed his silencer box. Yesterday another one did it do his truck. They like it so far too. Now were racing to see who can build his DIY smooth tube kit first. but I've got a secret weapon that I didn't tell them about. My ported TB on order....Muahhhaaaa.....