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402 Mileage/MPG?

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Old 03-15-2008, 11:01 PM
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Default 402 Mileage/MPG?

So i've got a forged 402 from TSP on the way. I've got pretty much everything for this motor. I'll be running 11:1 and a 244/248 113lsa cam. I should be just over 500 rwhp thru a 6 spd tranny.

I'm interested in knowing what I might be looking at as far a the live expectancy of this motor. Its not going to be ragged on and I might have to daily drive it for the next year or so. Am I looking at 50K, 100K, 125K???

Also, what kinda of gas mileage are these motors making? City and hwy? I'd be happy if I got 15/24. I probably wouldn't care so much if gas prices weren't so high, but more importantly...that i'd be driving it an average of 25miles a day for a while.
Old 03-16-2008, 08:03 AM
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So i've got a forged 402 from TSP on the way. I've got pretty much everything for this motor. I'll be running 11:1 and a 244/248 113lsa cam. I should be just over 500 rwhp thru a 6 spd tranny.
That's similar to the cam and compression I ran last year. It was a suprisingly streetable cam (with proper tuning).

I'm interested in knowing what I might be looking at as far a the live expectancy of this motor. Its not going to be ragged on and I might have to daily drive it for the next year or so. Am I looking at 50K, 100K, 125K???
That depends on the quality of the build and assuming the motor is broken in properly so the rings seat correctly. I'm pretty sure TSP uses Sunset Machine to build their shortblocks. SDPC uses them as well. My original short block was built by them and was good (no blow by and great oil pressure).

Also, what kinda of gas mileage are these motors making? City and hwy? I'd be happy if I got 15/24. I probably wouldn't care so much if gas prices weren't so high, but more importantly...that i'd be driving it an average of 25miles a day for a while.
A 6-speed should get that kind of mpg. However with a stroker, tunes comes into play for mpg to help maximize mileage. Last year I could easily get 15 mpg (A4, TC and 3.73) on the hwy and routinely saw 17-18 mpg if I stuck to the speed limit and didn't beat on it. Because of the big stall I run, city mpg sucks. Once again, it should be better with a 6-speed and good tuning.
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Old 03-16-2008, 10:05 AM
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I am getting 15/22 with an A4 and 3.42's. Open loop tune. Little less cam and compression.

-Geoff
Old 03-16-2008, 11:16 AM
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Originally Posted by White_Hawk
I am getting 15/22 with an A4 and 3.42's. Open loop tune. Little less cam and compression.

-Geoff

I get about 15 overall driving my M6 C5 anyway I want. I get about 21-22 on the highway. I run 3.90's. My build is pretty understressed and I would expect to get at least 100k from it.
Old 03-16-2008, 12:59 PM
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Yea, I was searching for MPG and have some pretty good ball park figures. I plan to break in the motor the right way. I need to call TSP about that. Once break in is done, its getting fully synthetic Mobile 1 every 3000mi.
Old 03-16-2008, 01:27 PM
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Jesus something is wrong with my car, I don't think I get anywhere NEAR that kind of mileage.... I'd be suprised if I got over 10 city driving. I haven't done any real highway driving.

But its hard to test because I try and get the "good driving" MPG and someone pisses me off and I have to say bye bye. Its amazing how fast other cars dissappear in my rear view mirror
Old 03-16-2008, 01:31 PM
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with the forged internals, be sure to always let it warm up a little before you dog it. it might even be worth getting an automatic starter and/or a oilpan prewarmer to decrease the start up wear. ihave an auto starter and always try to crank it before i actually get in and drive it. i think this helps alot more than one would think...
Old 03-16-2008, 03:28 PM
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I was always real gental with the car till everything was up to operating temps. I'm going to let it warm up on cold days before I get in to drive it too. It'll be in the garage at night though.
Old 03-16-2008, 06:44 PM
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I have a 402ci,248/256 cam,11.8.1compression,m6 w/4.11's. I have not drove my car alot but I did drive 70mi the other night (trying to get some miles on the new clutch)I used only slightly over 1/8 tank. Most were highway miles(breaking in the motor too)I was impressed on the gas mi for a 500+hp 3,600lbs car.
Old 03-16-2008, 07:07 PM
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Cool, I've got a bet with my friend that thinks he knows everything about cars. He's into mostly SBC/BBC trucks. He's saying I won't be getting anywhere near the gas mileage i'm expecting....more like single digits, maybe 10-12 hwy. He's also saying my motor is only going to last 50K miles maybe and that its going to overheat in warm weather. I don't think i'll be having these problems, but its got me thinking.
Old 03-16-2008, 07:22 PM
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I was getting 25 hwy with the stock 6.0L. Then we cammed it, LT headers and a 112 maggie.

It went to 22 hwy and 14 in town. Now we are building a stroked 402, ETP 225 heads and a overdriven maggie 122. God, I hope to see double digits in town.

Tom
Old 03-16-2008, 07:42 PM
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Originally Posted by HotWhipT/A
Cool, I've got a bet with my friend that thinks he knows everything about cars. He's into mostly SBC/BBC trucks. He's saying I won't be getting anywhere near the gas mileage i'm expecting....more like single digits, maybe 10-12 hwy. He's also saying my motor is only going to last 50K miles maybe and that its going to overheat in warm weather. I don't think i'll be having these problems, but its got me thinking.
Your friend is ignorant/old school. Sorry to tell you, but he's about 15-20 years behind the curve. You can have what you want, but it will cost you. You'll need a few things:
1. The right builder
2. The right tuner
3. To pick a smaller cam than the small *****/big cam crowd says
4. To get expert advice on how the PACKAGE will work together
This includes intake, motor, cam, heads, rotating assy., headers, etc.
5. Make sure it all fits with your priorities and intended usage

If you do it right, you can get what you want. Good luck staying off the loud pedal though.
Old 03-16-2008, 07:57 PM
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Originally Posted by jmilz28
Your friend is ignorant/old school. Sorry to tell you, but he's about 15-20 years behind the curve. You can have what you want, but it will cost you. You'll need a few things:
1. The right builder
2. The right tuner
3. To pick a smaller cam than the small *****/big cam crowd says
4. To get expert advice on how the PACKAGE will work together
This includes intake, motor, cam, heads, rotating assy., headers, etc.
5. Make sure it all fits with your priorities and intended usage

If you do it right, you can get what you want. Good luck staying off the loud pedal though.
I hear ya! Were always talking **** back and forth and its funny because i'm usually right, but he'll never admit it. I think I've got all my ducks in line for a good set up. I like to tell him my shortblock is worth more than his entire truck. He's got an old white 454 SS truck that runs like *** and makes 4 mpg.
Old 03-16-2008, 10:32 PM
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HOTWHIP- I have a friend like yours. He thinks he knows all and everything he has is better. I usually can put him in his place but he will also never admit it. Like the time he told me my new hummer h3 is a piece of **** and his s10 will kill me in any race. I put 3 cars on him in the 1/4mi and past 60mph 8 cars. so we went threw mudd and hills because he said I would get stuck...I did not get stuck at all. I'm now talking to him less and less because I can't stand his **** talking anymore. I'm woreout dealing with him for the last 8yrs. I also drove my car close to 100mi tonight and I'm easily getting 20-22mph at 70mph on the hwy. be cool bro..
Old 03-17-2008, 12:25 AM
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He's alright. He works with me too, so it passes time. I knew his brother before I knew him. They're all pretty goofy and their sister is hot, but damn she's ditsy! I can't stand her.

Once I get the car running...should be in the next 5 weeks or so, it'll still be a long time before I can show him up. Break in of course, but I still have the stock rearend! I have major plans for a rearend so I need it to last. I'm talking mini-tubbed with some custom forged wheels and air suspension. It all involves the rearend.
Old 03-17-2008, 03:47 AM
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Originally Posted by 93TAWicked1
Jesus something is wrong with my car, I don't think I get anywhere NEAR that kind of mileage.... I'd be suprised if I got over 10 city driving. I haven't done any real highway driving.

But its hard to test because I try and get the "good driving" MPG and someone pisses me off and I have to say bye bye. Its amazing how fast other cars dissappear in my rear view mirror
you have a heavier engine and bigger cubes..
Old 03-17-2008, 11:20 AM
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Originally Posted by 93TAWicked1
Jesus something is wrong with my car, I don't think I get anywhere NEAR that kind of mileage.... I'd be suprised if I got over 10 city driving. I haven't done any real highway driving.
Might be your tune. How is the idle tuned? It is amazing how big of a hit your mileage will make if it is idleing too rich or at too high of an RPM. Often caused by cracking the throttle body to keep it idling. You have to trick the O2's at idle, otherwise they will dump fuel like crazy.

-Geoff
Old 03-17-2008, 11:26 AM
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Originally Posted by White_Hawk
Might be your tune. How is the idle tuned? It is amazing how big of a hit your mileage will make if it is idleing too rich or at too high of an RPM. Often caused by cracking the throttle body to keep it idling. You have to trick the O2's at idle, otherwise they will dump fuel like crazy.

-Geoff

I know I'm still on a 346 but I can vouch for that. When I go to the track and idle for 30 minutes waiting to get in my car uses more gas than on the 20 minute drive to the track. I seriously idled out an 1/8th of a tank last week in ~35 minutes.
Old 03-17-2008, 11:29 AM
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Hmmm you guys bring up a good point. The car was dyno tuned by a well regarded tuner in the vette community, but it was done on a Mustang dyno and while the WOT is spot on, I've not been happy with the idle. It will stay at like 2k when you come to a stop then after 5 seconds go down to 900. Whats really wierd to me is if I'm at highway speeds and put in the clutch it will stay at 2k indefinately which makes no sense to me.

I have V2 EFI live I plan on working on it this summer. I am just not sure how to use it for idle tuning...
Old 03-17-2008, 11:47 AM
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Originally Posted by White_Hawk
You have to trick the O2's at idle, otherwise they will dump fuel like crazy.

-Geoff
What 02's? I don't have any. I run open loop MAF.


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