Efficiency Question

StangBanger302 · February 6th, 2011, 09:27 PM

I was wondering, should I go for an N/A 347 combo? Or a 302 boost one? I'm not talking about money now, I mean efficiency. Will a properly matched 347 get ok gas mileage? I just wouldn't want to build a nasty N/A car, to fill it up every two days. But, if I go boost, I can get good gas mileage, considering what power it has. I was thinking about an Ed Curtis cam, with Foxlake ported Twisted wedge heads and a matching intake with 30# injectors, 90mm MAF etc. Thoughts?

jessemachone · February 6th, 2011, 09:33 PM

boost does not equal good gas milage.

StangBanger302 · February 6th, 2011, 09:40 PM

I know a local guy, has the same heads as me with a little porting, mild custom cam, edelbrock performer intake, vortech blower @ 16psi with a tremec 3550 and he gets 18 mpg....I would think an N/A car getting 525RWHP would be less efficient. I thought if you have a forced induction car, and stay OUT of boost, you can get good gas mileage?

jessemachone · February 6th, 2011, 09:42 PM

what is the point if you stay out of boost? I do understand what you are trying to say.

Get a Prius.

StangBanger302 · February 6th, 2011, 09:45 PM

^^^ So if I want to just cruise, I don't dump all my fuel...This isn't helping with my question.

fogged306 · February 6th, 2011, 09:59 PM

Boosted cars always require more fuel than N/A cars to make the same amt of power. The fact that they run at richer A/F ratios proves this. I do kind of get what you're saying about part throttle though, and you may actually be right. Less cubes will require less fuel. If you stay out of the boost and tune the car to be as efficient at part throttle will the lower A/F ratio, smaller cube engine use less fuel than the higher A/F larger cube engine? I think that's kind of a valid question and I'm kind of curious to know what people have to say about it too.

jessemachone · February 6th, 2011, 10:00 PM

The super charger is going to drag down the engine. A turbo will drag it down but not as much as a supercharger.

A good breathing N/A motor is your best bet. 1slo5.0 built a mild 306 that ran in the 11's and I think he said he was getting 23 - 25 mpg.

fogged306 · February 6th, 2011, 10:07 PM

Originally Posted by jessemachone

The super charger is going to drag down the engine. A turbo will drag it down but not as much as a supercharger.
.

good point, I didn't take that into account.

StangBanger302 · February 6th, 2011, 10:21 PM

I would do a turbo...Runs off of exhaust gasses and is more efficient. And I mean, at part throttle the turbo will make more power than the N/A vehivle, and it will be moving the same amount of weight...Which will make it move easier by using the same amount of fuel...I don't know. I'm thinking too hard...I need more opinions. But I'm debating between the two. Boost 302 - N/A 347. Both stock blocks for now. And yeah, he ran 11.6 and got 25mog on the highway. But my thought out combo is more aggressive than that out of the box one. Custom cam, ported heads, and high flowing intake etc.

jessemachone · February 6th, 2011, 11:25 PM

Part throttle, it will not make the same power as a built NA set up.

opinions are like assholes.....

Do some research for some hard core facts. Talk to people who have done it already. Don't take a person's advice on a turbo if they are NA and vice versa. I am just trying to help you with the facts.

So far, I have seen opinions and feelings with no facts.

The Turbo Forums.com

Immerse yourself in the knowledge base for a while. Prepare for your frontal lobe to melt

You should also identify your purpose for this build. Will it be for street with some track? Track with some street? All track? Road course? All street?

1slo5.0 · February 7th, 2011, 07:55 AM

A friend of mine has a 347 and a 5 speed and a CARBURETOR. He gets 23mpg on the highway. My old 306 did 25mpg on the highway. With a blower or turbo, the tune is going to be what matters.

StangBanger302 · February 7th, 2011, 01:02 PM

Let's narrow this down. The car will be street/racing....Sometime at the track, and sometimes getting down other places. I want it to be quick, and still streetable. Lookin for 420-450 at the tire range...Basically wanna run mid to maybe low 10's and still be streetable.

nolife · February 7th, 2011, 03:04 PM

My supercharged 5.0 that is more than your 420+ ballpark gets almost the same MPG as my other 5.0 which is bone stock and 2.73's in average around town driving. It depends on how and where you drive it.

VM0824 · February 7th, 2011, 03:34 PM

i dont get 25mpg in my bolt-on 225hp stang

69fastback · February 7th, 2011, 03:42 PM

I think in the end, it's nearly a wash. Either way, the tune, and your right foot will be the deciding factor.

1slo5.0 · February 7th, 2011, 03:48 PM

Originally Posted by StangBanger302

Let's narrow this down. The car will be street/racing....Sometime at the track, and sometimes getting down other places. I want it to be quick, and still streetable. Lookin for 420-450 at the tire range...Basically wanna run mid to maybe low 10's and still be streetable.

10s and streetable is very possible, especially with a power adder.

StangBanger302 · February 7th, 2011, 04:39 PM

Originally Posted by 1slo5.0

10s and streetable is very possible, especially with a power adder.

Let's just say naturally aspirated....How do you think that would be? I've just never seen many 347s do 10's.....lol

1slo5.0 · February 7th, 2011, 04:56 PM

Originally Posted by StangBanger302

Let's just say naturally aspirated....How do you think that would be? I've just never seen many 347s do 10's.....lol

You need to look harder. There are alot of 302/306s in the 10s. I had a nitrous car with a 347 that ran 10.80s on motor alone. This was with a nitrous set up (tight converter and tight gearing). The guy that owned my black car before me had a 347 and some off the shelf, nothing special parts and went mid 10s. In all honesty if you can run at least a 10.80 with a naturally aspirated 347 powered Mustang then you need to quit the hobby and get into scrapbooking instead...

StangBanger302 · February 7th, 2011, 07:20 PM

That gives me some hope then! Thanks...And listen to this, guy on youtube had the 2.02 valve version of my heads with an e-cam and a trickflow intake (holy mismatch) with supporting mods, and he only picked up 3 tenths by going to a 347....But alright, I'll stick to my plan and se how it works out. Thanks guys!

69fastback · February 7th, 2011, 07:42 PM

Did he used the same combo on the 347 as the 302?

February 6th, 2011, 09:27 PM	#1
StangBanger302 Hardcore Enthusiast 1992 Mustang LX 13.0 @ 105 Join Date: Jun 2010 Location: New York Posts: 2,230 iTrader: 0 reviews	Efficiency Question I was wondering, should I go for an N/A 347 combo? Or a 302 boost one? I'm not talking about money now, I mean efficiency. Will a properly matched 347 get ok gas mileage? I just wouldn't want to build a nasty N/A car, to fill it up every two days. But, if I go boost, I can get good gas mileage, considering what power it has. I was thinking about an Ed Curtis cam, with Foxlake ported Twisted wedge heads and a matching intake with 30# injectors, 90mm MAF etc. Thoughts? __________________ As I lay rubber down the street I pray for traction I can keep But if I spin, and begin to slide Please dear God, protect my ride

February 6th, 2011, 09:40 PM	#3
StangBanger302 Hardcore Enthusiast 1992 Mustang LX 13.0 @ 105 Join Date: Jun 2010 Location: New York Posts: 2,230 iTrader: 0 reviews	I know a local guy, has the same heads as me with a little porting, mild custom cam, edelbrock performer intake, vortech blower @ 16psi with a tremec 3550 and he gets 18 mpg....I would think an N/A car getting 525RWHP would be less efficient. I thought if you have a forced induction car, and stay OUT of boost, you can get good gas mileage? __________________ As I lay rubber down the street I pray for traction I can keep But if I spin, and begin to slide Please dear God, protect my ride

February 6th, 2011, 09:45 PM	#5
StangBanger302 Hardcore Enthusiast 1992 Mustang LX 13.0 @ 105 Join Date: Jun 2010 Location: New York Posts: 2,230 iTrader: 0 reviews	^^^ So if I want to just cruise, I don't dump all my fuel...This isn't helping with my question. __________________ As I lay rubber down the street I pray for traction I can keep But if I spin, and begin to slide Please dear God, protect my ride

February 6th, 2011, 10:21 PM	#9
StangBanger302 Hardcore Enthusiast 1992 Mustang LX 13.0 @ 105 Join Date: Jun 2010 Location: New York Posts: 2,230 iTrader: 0 reviews	I would do a turbo...Runs off of exhaust gasses and is more efficient. And I mean, at part throttle the turbo will make more power than the N/A vehivle, and it will be moving the same amount of weight...Which will make it move easier by using the same amount of fuel...I don't know. I'm thinking too hard...I need more opinions. But I'm debating between the two. Boost 302 - N/A 347. Both stock blocks for now. And yeah, he ran 11.6 and got 25mog on the highway. But my thought out combo is more aggressive than that out of the box one. Custom cam, ported heads, and high flowing intake etc. __________________ As I lay rubber down the street I pray for traction I can keep But if I spin, and begin to slide Please dear God, protect my ride

February 7th, 2011, 07:55 AM	#11
1slo5.0 MM Ninjas! 1990 Mustang LX 9.36@143 mph Join Date: Jan 2006 Location: North Fond du Lac, Wisconsin Posts: 11,375 iTrader: 1 reviews	A friend of mine has a 347 and a 5 speed and a CARBURETOR. He gets 23mpg on the highway. My old 306 did 25mpg on the highway. With a blower or turbo, the tune is going to be what matters. __________________ My daily driver has 16 cylinders and 4400hp @ 1000 rpm.... ***1988 Mustang GT - Stock....almost

February 6th, 2011, 09:59 PM	#6
fogged306 MM Fanatic 89 GT Join Date: Apr 2007 Location: NY Posts: 4,875 iTrader: 2 reviews	Boosted cars always require more fuel than N/A cars to make the same amt of power. The fact that they run at richer A/F ratios proves this. I do kind of get what you're saying about part throttle though, and you may actually be right. Less cubes will require less fuel. If you stay out of the boost and tune the car to be as efficient at part throttle will the lower A/F ratio, smaller cube engine use less fuel than the higher A/F larger cube engine? I think that's kind of a valid question and I'm kind of curious to know what people have to say about it too.

February 7th, 2011, 01:02 PM	#12
StangBanger302 Hardcore Enthusiast 1992 Mustang LX 13.0 @ 105 Join Date: Jun 2010 Location: New York Posts: 2,230 iTrader: 0 reviews	Let's narrow this down. The car will be street/racing....Sometime at the track, and sometimes getting down other places. I want it to be quick, and still streetable. Lookin for 420-450 at the tire range...Basically wanna run mid to maybe low 10's and still be streetable. __________________ As I lay rubber down the street I pray for traction I can keep But if I spin, and begin to slide Please dear God, protect my ride

February 7th, 2011, 03:04 PM	#13
nolife MM Fanatic 91GT, 88GT, 02GT Join Date: Dec 2006 Posts: 3,057 Blog Entries: 3 iTrader: 0 reviews	My supercharged 5.0 that is more than your 420+ ballpark gets almost the same MPG as my other 5.0 which is bone stock and 2.73's in average around town driving. It depends on how and where you drive it. __________________ Last edited by nolife; February 7th, 2011 at 03:13 PM.

February 7th, 2011, 03:34 PM	#14
VM0824 Regular 1989 Mustang GT ~14@99 (b4 turbo) Join Date: Mar 2010 Location: Pt Pleasant, NJ Posts: 455 iTrader: 0 reviews	i dont get 25mpg in my bolt-on 225hp stang __________________ 306 w/ 8.9:1 ON3 70mm turbo kit - 9#'s boost arp chromoly studs 47# FRPP - 255 walbro 3.73 - tremec 3550 - zoom hp kevlar clutch msd 6a + blaster coil lowered. sfc. HID delete egr-smog-cats-a/c-foglights battery reloc QuarterHorse, BE, EA

February 7th, 2011, 03:42 PM	#15
69fastback Premium Member 1969 Mustang Mach 1 6.824@101.61 Join Date: Aug 2006 Location: Oklahoma jackass, get to driving Posts: 5,565 iTrader: 0 reviews	I think in the end, it's nearly a wash. Either way, the tune, and your right foot will be the deciding factor. __________________ ./___ _ ____ ___ \. ( ]]] _ _ O _ _ [[[ ) \_ o _ _____ _ o _/ \|___\| ......... \|___\| http://www.youtube.com/watch?v=HyYU3...e_gdata_player

February 7th, 2011, 07:20 PM	#19
StangBanger302 Hardcore Enthusiast 1992 Mustang LX 13.0 @ 105 Join Date: Jun 2010 Location: New York Posts: 2,230 iTrader: 0 reviews	That gives me some hope then! Thanks...And listen to this, guy on youtube had the 2.02 valve version of my heads with an e-cam and a trickflow intake (holy mismatch) with supporting mods, and he only picked up 3 tenths by going to a 347....But alright, I'll stick to my plan and se how it works out. Thanks guys! __________________ As I lay rubber down the street I pray for traction I can keep But if I spin, and begin to slide Please dear God, protect my ride

February 7th, 2011, 07:42 PM	#20
69fastback Premium Member 1969 Mustang Mach 1 6.824@101.61 Join Date: Aug 2006 Location: Oklahoma jackass, get to driving Posts: 5,565 iTrader: 0 reviews	Did he used the same combo on the 347 as the 302? __________________ ./___ _ ____ ___ \. ( ]]] _ _ O _ _ [[[ ) \_ o _ _____ _ o _/ \|___\| ......... \|___\| http://www.youtube.com/watch?v=HyYU3...e_gdata_player

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