After perusing the site for an answer to this question, I failed to find one and I'm hoping that some of you can help me out. What I'm trying to find out is if installing one of these "no tune required" CAIs actually leans the LT1 out enough to be a danger to the engine. Has anyone data logged after installing a CAI with no other mods? What were the effects on the A/F ratio at WOT? How about spirited driving below WOT? The only thing I have done to my car is to add the B&B Fusion exhaust. I don't track my car or run it really hard, so I'm just trying to see what adding a CAI would do without a tune. Not interested in a tune right now. Thanks!

 

If an intake is your only planned mod, don't waste your time or money. You definitely won't get any noticeable performance gain with a tune and definitely nothing without a tune. But to answer your question, any aftermarket intake is going to alter the cars fuel trims and might even make the car slower without a tune. The most danger you are in without a tune is when the cars fuel trims haven't adjusted for the changes. You risk running lean here, but you could also run rich, depends on the intake. It's likely that a CAI alone won't lean it out enough to cause any damage, I mean its very rare that is the case. But I go back to my first sentence, CAI only is a waste. If you plan to do supporting mods AND a tune, then a CAI is an important piece of the whole package.

CAI and ported intake manifold with a tune would be the minimum mods I would start with. Anything less is a waste. Might not be the answer you wanted. But if you really are hell bent on adding only a CAI without a tune, you probably won't blow up your engine. But if you do, you might have a hard time getting GM to cover it.

 

TriPinTaZ,

What are your thoughts on just changing to a BMS air filter with no other mods or a tune, concerning fuel trims, and any real gains, or losses, in power or drivability on a LT1?? (not LT4)


.

 

Thanks for the response. I'm very aware of everything you suggested, having built a cammed and blown 2008 Mustang GT and a cammed 2015 Camaro SS in years past. I hear a lot about the Vararam intake and how it improves throttle response somewhat. All I'm trying to achieve is better go-pedal response and perhaps a bump in power. Even though my 'Vette is just a base 1LT, I can't afford to take a chance on tuning right now (7k miles) due to the cost of repairs/parts on these vehicles. I am satisfied with the power this car has, so I'm not going to put my warranty at risk right now. Anyway, thanks again for your response. I appreciate it.

 

Slick , I have the Vararam and I have extensively data logged my car before and after mods during my track runs . Yep your fuel trims will bounce around and finally settle in . My experience is ... it's not about a CAI increasing HP , it's about the ECM not pulling timing when the IAT temps are above 85.
Also in my experience You also will not slow your car down by installing it
The first WOT run down the track I popped a CEL for lean miss multiple cylinders. I think that was caused by a combination of the ST and LT fuel trims were still bouncing around and the fact that I did not richen up WOT yet
I reset the light and proceeded to do several more runs without a problem . The CAI has now been on my car which I drive a lot for over 6 months .. I have run and logged the car many nights where before install the ECM would pull timing and now after there is no timing retard
One benefit, because it is open at the top , when you jump down hard the intake sounds like my Big Block Chev
This is one mod you will be happy you did
Dave

 

The BMS air filter actually makes power due to the fact that the opening at the base of the filter is larger than the OEM filter or most aftermarket ones like K&N. What this does is decrease the intake resistance AND(the most important part) it actually slows down the perceived velocity of the air crossing the MAF sensor. This results in the ECU thinking that less air is coming into the engine since the MAF frequency is now technically incorrect. So with the BMS filter 5% more air is entering the engine than it would be with the stock filter at the same MAF frequency. The ECU doesn't know about this 5% more air and still injects the same amount of fuel, leaning out the fuel mixture and making more power. However, since the intake tract and diameter are still stock, the fuel trims don't go all crazy. They will eventually go positive and add fuel to compensate for what the O2's are seeing and this will negate some of the gains you saw when you first installed the filter. Another positive is that since the factory intake is still on the car, it won't change the perceived intake air temps and you won't have any sort of additional timing being pulled out by the ECU. So in summary, the BMS filter is a pretty safe bet. You will lose half of the gains in HP once the fuel trims adjust, but they will be stable. I wouldn't worry about just adding a BMS filter at all. My only recommendation on this would be to reset the fuel trims if you have a capable data logger or pull the battery power for 10 minutes after the BMS filter install. You want the ECU to have 0% fuel trims when the BMS filter is first used so that it will adjust quicker to the air flow changes.


Any aftermarket intake will actually increase observed Intake Air Temps in stop and go traffic on hot days. On the factory tune the car will pull a lot of timing and the car will feel very sluggish. The ST and LT fuel trims bouncing around will also cause inconsistencies in performance when driving. At times the car will feel like it is up 25HP and then at others you will swear it is down 25HP. Now the LT4's will pick up power without a tune but they will also have this weird FT variance. If anyone is comfortable with this then they can do as they please. The fuel trim variances are not severe enough in 99% of the operating scenarios the car will see to damage the engine. I certainly would not track the car though. (race track not drag racing)

 

This holds true only till the MAF and the ECU compensates …. on an LT1 there is no power to be had installing a bigger or better "air filter"as the STOCK air filter will out flow the engine's needs . Now on a LT4 there are proven gains as the AIR FILTER is a choke point ….

Not sure this is entirely true as How will " ANY AFTERMARKET CAI" actually increase observed ITA's ? Any Air intake , and not just an aftermarket intake will see an increase in stop and go traffic just as the stock Intake

The object of a CAI is to pull in as close to ambient air temps as possible thereby reduce the tendency of the ECU to pull timing , some Cold Air intakes are better than others at doing this but I can speak to the fact that the VARARAM does work and is the only one that is not limited to pulling the air from inside the fender well , the same place the factory air intake pulls from ….. I have many many data logs to prove that my ECM is not pulling as much timing and the IAT's cool down way faster compared to not running the VARARAM

The LT and ST trims only bounce around for the first 25 miles or so and yes I agree I would not race with them bouncing this was my mistake when I popped a CEL as I ran the car , went home installed the VARARAM and then went back without putting any real miles on the car but once again , as soon as the ECM adjusts positive they are steady as a rock

I was lucky this year , we had a month of the same crappy temps and weather , I baselined my car stock and then as I did each mod I would record the temps , DA and Grains using several tools one of them is AIR DENSITY ONLINE, while not perfect this and my data logs allowed me to come close to see what the car was doing and why ...
http://airdensityonline.com/track-fo...lanta_Dragway/


On back to back track days, running the car the same time of day each day with the same terrible temps and DA (high 80's and 3,000 DA ) with almost the same 60 FT times using launch control and without a tune on my LT1 I did some comparisons without and with the VARARAM installed , and the ECM pulled a lot less timing and picked up almost 3 tenths in the quarter

The OP asked if he could install a CAI without a tune , the answer is yes , the ECM will adjust , the long term and short term fuel trims will settle and you will not cause any harm , will it feel like you gained 50 HP off the bat with a VARARAM , maybe but as soon as the ECU adjusts that number is lower but once again its not about how much power a CAI will gain on an LT1 , its about making all the power that the motor is capable of delivering

He also asked if installing a BMS filter would show any gain , unless you have MODS on an LT1 ( Blower , Cam , Heads etc ) then the answer is save your money , if you have mods or an LT4 , then answer is yes



Dave

 

^^^

Check the IAT's on any car with an aftermarket intake. The IAT reads higher temps. Not that they are actually higher, it is just that the aftermarket material and design vs OEM does not do as good of a job at avoiding heat transfer or sucking in hot air when the car isn't moving. This is easy fixed with a tune by changing the operating range where the ECU pulls IAT related timing. Hence why my wording was "observed intake temps". And also that was one of my specific reasons why my advice earlier in this thread was a CAI without a tune is a waste.

Regardless of what your suggestion/opinion is and that it differs from mine does not make either of us wrong. I'm only stating facts from my experience tuning cars but that does not mean that I know everything or am always right. It is up to the OP to decide what suggestions best align with what he is comfortable with. I do agree with you, as stated in my first post, that a CAI is a waste of money without a tune.

 

Dave would you think a BMS filter, Soler tb, Hooker shorty headers, and Akrapovic lip on exhausts on a 19 z would require a tune? The headers are mostly for the weight reduction. They weigh 22 lbs less than my factory manifolds. The exhaust is a little over 19 lbs lighter than stock. I do a lot of hpde's so weight reduction makes a difference. Thanks

Herman

 

Herman , I would venture to guess that the BMS filter will be no problem at all as far as setting a CEL as long as you drive it a bit to let the fuel trims to stabilize, I did jump down hard on my car to soon after the Vararam install and set a CEL but it reset after a few starts

The Solar TB , you will have absolutely no issues with setting a code and the Hooker Shorties becasue they use the stock down pipe and keep the O2 sensor pretty close to the OEM location should also not cause any issues
Have fun with the racing , make sure you post some pictures
Dave

 

Will do. Thanks Dave.

 

this is interesting....from what I read, installing the Solar TB, Vararam CAi and a Xpipe would not require a tune....

sounds like there might be differing opinions on here, is that still not the case?

 

personally, adding this much change to the car...I would definitely get it tuned. Thats me tho...

 

Complete waste of money , the fuel trims will more than compensate for the Vararam , as far as the solar throttle body and x pipe, they will not affect the stock tune at all .......

Dave

 

During install unhook the battery wait 10 mins rehook battery and then drive it it will adjust itself.

 

No need to unhook the battery to rest fuel trims , that's what the O2 sensors are for ..., as soon as you start the car first time the fuel trims will begin to adjust the closed loop ( part throttle conditions ) and after a few miles all will be fine

As far as open loop (wide open throttle) these cars run way rich and you will not have any issues
The only reason to unhook the battery is if you are unplugging the MAF sensor as this has been known to set a code sometimes . I chose to just unscrew the MAF from the MAF tube without disconnecting the wires to avoid this issue

Dave

 

I agree. When I unhooked my maf sensor Sunday to replace the filter it threw codes and went into reduced power mode. I shut it down, rechecked everything, cleared the codes, and it ran fine. The 19's will throw a code if the maf sensor is unplugged. It doesn't matter that the engine isn't running.

 

Sorry , I should have warned you sooner ……

Dave

 

My fault. I didn't ask my questions until I'd already done it. Thanks for your help and advice.

 

just got the vararam on in addition to the solar tb/tc and no issues at all with cel plus car is running and sounds great...you can hear the intake sucking and got some extra volume....performance wise the car feels much better with the combination, most im sure is coming from the responosiveness, but its a much better setup and feels like a vette now.

cant wait to get the xpipe on in a week and complete the trifecta