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Thread: MPG with new cam?
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04-03-2008, 03:42 PM #1
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MPG with new cam?
What kind of street-ability and MPG am I looking at with a comp 224/236 114 LSA cam? on a 94 Z/28 A4 with pacesetter mids and SLP LM-1
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04-03-2008, 04:35 PM #2
If you have a bigger stall to go with that cam... MPG= NO
All kidding aside, that isnt too big of a cam, but nonetheless dont expect anything too spectacular for gas mileage. It would just be a guess without knowing if the car has a converter, tune, or different rear gears (not to mention your driving style)... but maybe 13-14 city, 20-22ish highway.
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04-03-2008, 05:43 PM #3
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well thats not too bad considering I already only get like 15 in town would this cam be worth it to spend 165 on or should I just save up and get a bigger one?
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04-04-2008, 12:37 AM #4
Cams are cheap... its all the shit you need with one to do it right thats expensive... and the tuning, etc
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04-04-2008, 06:16 AM #5
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Black- '96 Impala SS & '14 SS
A while back, I had a similar cam in my Impala. I had the following Comp Cams Lobes with 1.6 rockers and a 114* LSA:
Intake -- #3192 -- 224* duration -- .605"
Exhaust - #3194 -- 230* duration -- .622"
With 3.73 gears, 3000 stall Yank TC an a 396ci stroker, I got 21 MPG Hwy and 14 MPG City.
This was with a 4100LB car that ran mid-12's in the 1/4 mile .
The next cam I buy for my Caprice (same set-up the SS had) will have the same intake lobe except the exhaust lobe will be #3196. That's a 236* duration with .624" lift and a 110* LSA.....it will have 10* overlap.
The cam you propse will have minimal (if any) overlap....maybe 2 to 6 degrees. This means it will have minimal lope, be fairly easy to tune, get good gas mileage and pass emissions standards that you have in your area.....if you have a good tune.
In an F-body, I suspect that you'll have gas mileage similar to what I had in my SS. With good heads, you can make very good power......but you'll still leave a bit 'on the table' if you're going NA. You should be able to easily run mid- to low-12's with the right gears/TC.
Have fun.
KWLast edited by KW Baraka; 04-04-2008 at 06:24 AM.
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04-04-2008, 07:47 AM #6
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Quicksilver- 03 Corvette Z06
KW has some great info. We disagree on what size T/B to run is very good with the LTX motors.
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04-04-2008, 11:16 AM #7
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04-04-2008, 11:27 AM #8
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Black- '96 Impala SS & '14 SS
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04-04-2008, 11:30 PM #9
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04-04-2008, 11:35 PM #10
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white- 94 camaro z28
my car was restricted by the stock one once I did valve train and 181cc port. stock tb is not big enough if you are modding at all. a 52 will support up to 400hp without restriction though. the 48 stock one restricts even stock power slightly. if you get one with an airfoil it will help even more. an air foil alone on a stock car will help alot (notiecable gain. maybe 5hp)
edit: right now mine is just a stock tb ported out to 50mm with an air foil modded to fit in. I will eventually get an edelbrock 52mm
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04-05-2008, 01:14 AM #11
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04-05-2008, 01:29 AM #12
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white- 94 camaro z28
go look it up dumbass. read the flow of the heads and all then compare it to the throttle body. the stock throttle body does restrict it. with an airfoil it flows considerably better because there is not a flat piece in the center that creates turbulence. there is a reason why there are over 20 different throttle bodies for the lt1. if you have your heads ported at all you almost have to have a bigger one. I have a 181cc intake runner so I need a bigger one to flow enough for them.
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04-05-2008, 08:19 AM #13
Larger throttle bodies are probably the biggest wastes of money for an LT1. The 48mm throttle body will supply adequate flow for most applications. On a "street" heads/cam motor, you may see a slight increase by stepping up to a 58mm unit, but by no means is the stock 48mm "highly" restrictive. Most people dispute this theory, and as a result waste $300+ on a TB and gain virtually nothing. Larger throttle bodies are only going to be significant in the case of a more extensively built motor. I've seen some good gains on large heads/cam 355's, and 383/396 stroker setups. As far as mild street combos, your not gonna see much - if anything at all.
As for TB Air foils, 5rwhp is a bit over exaggerated. Dyno tests have proven 1-1.8rwhp, which isn't much of a gain, but for as little as $30 - why not.
P.S. Before you criticize, please do some researching first. Thanx!
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04-05-2008, 08:38 AM #14
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Quicksilver- 03 Corvette Z06
Here we go. Good info. But 15 HP in the middle and an overall average of 10 hp on the T/B alone is worth it to me. This being on a completly stock car. A 48 will suffice but a 52 would be better. Plus the Holley's are just so damn good looking its a shame to cover it with the intake.
This post makes me umm. I don't know never mind. Lets determine what "highly" means. So you have 8 cylinders, 210 cfm intake per cylinder at 100% VE. Ok we are not going to run 100% through the port lets say 60% 210 x .60 = 126 x 8 = 1008 cfm demand. The holley 52mm flows 1200 cfm so what do you think a stocker flows? Now what do you think a Cam'd car is going to run for VE 75% maybe? Hmm What about a true street strip car? Hmmm. Are we seeing a trend? So yes I would say the stocker is highly restrictive to anything BUT completly stock with paper filter. As KW knows, I dont think you should go to big Like a 58, but I do think a 52 would be in order.
P.S. I have done ALOT of research.
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04-05-2008, 10:01 AM #15
I'd be willing to bet you were not aware that GM uses the same 48mm diameter throttle body on their big block 502! Pure and simple you don't need a larger one unless you've done some serious modifications to the engine, this should certainly never be an early modification. Everybody thinks that the throttle body is a great modification because it's easy to change and it gives a "seat of the pants" power increase. The reason the car feels faster is because for any given amount of pedal travel, more air is allowed into the engine. Say if you press the pedal 10% it's the same effect as pressing it 15%, so it feels faster. The problem here is that by say 75% throttle, the engine is already flowing as much air as it possibly can, this means that the top 25% of the pedal is completely dead travel. The car may feel faster, but as far as power is concerned, it isn't. This modification ranks right up there with the throttle performance switch, you are paying money to have the same effect as pressing the gas pedal, which is simply not worth it. After enough modifications are performed such as cylinder head upgrades, cams and exhaust a larger throttle body may be of some benefit. Unfortunately the exact point at which a larger throttle body might become useful is impossible to quantify. As such I list it as not completely useless, but nearly so.
Dyno tests and personal experiences have backed my statement time and time again.
Here's some other "LT1 TB" feedback as well http://www.ls1tech.com/forums/archiv.../t-432364.html
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04-05-2008, 10:47 AM #16
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Quicksilver- 03 Corvette Z06
"Actually, it's not the valvetrain or reciprocating assembly that is the 502's effective rev limiter; it's the throttle body.
"Its limit is simply less than the engine's capability," explained Martin. "The engine would definitely make more power with a bigger throttle body."
^^^ This is a Direct quote from super chevy and Martin Motor sports about your 502.
Also your reference to the throttle position is not completly correct. At 15% throttle on a 48, 52, 58, shoot 100mm T/B has no reference as for the performance. Its the amount of air the MAP and MAF reads referenced to the position. You feel the seat of the pants feel because there is more air available at those positions. This changes the average HP not just the Peak. Average is better then Peak. So like I was saying. even if at 75 % you think you are at max flow, you are not, even with the bigger throttle body. You have yet to go WOT.
Over all I am not saying you should swap out the T/B on a stock car, or even a bolt on car. But if are puting in a cam get a 52mm. If you are building a stroker Get a 58mm.
EDIT: Please do not make a reference to what I may or may not know. Thanks.
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04-05-2008, 10:55 AM #17
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04-05-2008, 11:12 AM #18
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Quicksilver- 03 Corvette Z06
What? Thats it? No reasonable arguement or corrections? You will have to forgive my format. I am at work and have little time to worry about it.
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04-05-2008, 12:42 PM #19
Dumbass? this is your one and only warning. Next time you resort to name calling you're gone. I dont mind when anyone disagrees with me, but do it tactfully, 17 years old or not.
As for the TB argument here... there's no denying you're going to gain power, even on a stock motor. If 1-2rwhp is what you're looking for, get a bigger throttle body. I've seen badass heads/cam motors gain 3-4rwhp. I myself wouldnt bother upgrading until at least 400rwhp.
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04-05-2008, 03:37 PM #20
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