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N/A vs power adder


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larger ci n/a blocks vs turbos on smaller blocks

 

I'm curious because I have never been in a car with more than a 427. I'm not sure how much drivability is lost with lets say a 500ci or higher motor. I've also never been in a car that made over 800hp on a blower so I dont know how much lag you have to deal with, etc.

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larger ci n/a blocks vs turbos on smaller blocks

 

I'm curious because I have never been in a car with more than a 427. I'm not sure how much drivability is lost with lets say a 500ci or higher motor. I've also never been in a car that made over 800hp on a blower so I dont know how much lag you have to deal with, etc.

Depends on compression ratio, cam size, and head size as to how "streetable" it is. I've been on a ride in a few 502ci+ cars, and they've been extremely well manered on the street. It's all in how you match the parts. Race parts should stay RACE parts aka spools.

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So what's the gas mileage like on the well mannered ones?

 

Forced induction will be better in off-boost driving states then their larger NA performance counter part. Even with lower compression, intake and exhaust restriction, and overall lower off-boost efficiency, the cam and head profile can be more OEM matched. To get the same power out of displacement, you'll need a cam/head/intake that optimize power with rpm - making it inefficent out of that powerband.

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larger ci n/a blocks vs turbos on smaller blocks

 

I'm curious because I have never been in a car with more than a 427. I'm not sure how much drivability is lost with lets say a 500ci or higher motor. I've also never been in a car that made over 800hp on a blower so I dont know how much lag you have to deal with, etc.

 

 

A big inch engine built with good compression but under 12:1 is still very street able, and with todays aftermarket heads they can still be on pump gas with the right tune....plus turned up on race fuel you get the extra power...cams dont play much of a part for street able as much as they do street comfort....

 

Blowers don't have lag they are very responsive, its the bigger turbos on small engines that can produce the lag your talking about and with todays turbo's its not that bad...plus if ya want it to spool up fast shoot it with a 75 shot on the hit and have it shut off at a rpm you know the turbo will take over....

 

this is a very quick overview of the three and the discussions on all three can get pretty deep.

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Ive been in 1 car with a 540ci BBC with a 1071 sitting on top of it, and a plate kit sitting under that. With me sitting in it, and extra 225lb (at the time) it still went ~8.40s. It was nasty, and the fastest car ive ever had the priviledge to ride in. it was by no means drivin on the street... it probaby could have, but it was a drag chassis.
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A big inch engine built with good compression but under 12:1 is still very street able, and with todays aftermarket heads they can still be on pump gas with the right tune....plus turned up on race fuel you get the extra power...cams dont play much of a part for street able as much as they do street comfort....

 

Blowers don't have lag they are very responsive, its the bigger turbos on small engines that can produce the lag your talking about and with todays turbo's its not that bad...plus if ya want it to spool up fast shoot it with a 75 shot on the hit and have it shut off at a rpm you know the turbo will take over....

 

this is a very quick overview of the three and the discussions on all three can get pretty deep.

 

youre confused with what brian is asking, because you dont know brian, or anything about brians intentions in the other 2 posts youve made.

 

Brian wants turbos... a turbo, like a roots, twin screw, whipple, or centripital, is also known as a blower. What Brian is asking, is how bad the lag is on a turbo V8.

 

Brian, keep in mind... its still a V8, but now it has extra shit on top of it. Its still going to shit and get initially, but then the onset is going to make things that much better. Lag is one thing you do NOT have to worry about.

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I already know what I'm putting in the TA in 09. I was just curious about the streetability of the others cars out there. Like the Evo that went 9 flat at Norwalk. Can cars that run 8's be tuned so that you can drive them on the street and still get 19 miles to the gallon? After my truck lease is over I might want to get a 4 or 6 banger that can be driven in the winter and still kick ass at the track. This way when the TA breaks down I'll have a backup thats not an Envoy :mad: This summer FTL!!!

 

Edit: Wanna play halo? I just replaced the fan so it shouldnt overheat again.

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So what's the gas mileage like on the well mannered ones?

That would fall upon, transmission, and gear ratio then usually. Granted they won't be as good as a honda civic, but I've seen well mannered beasts getting upwards of 15 MPG with a hayes OD unit or an OD transmission. It's all in how much you get into it.

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That would fall upon, transmission, and gear ratio then usually. Granted they won't be as good as a honda civic, but I've seen well mannered beasts getting upwards of 15 MPG with a hayes OD unit or an OD transmission. It's all in how much you get into it.

 

Which with turbos, gearing can be very steep, as the powerband is broad. 2.93-3.22, OEM final drives...

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Guest ihuntv8

When building a fast car, who cares about gas mileage? First figure out how fast you want to go! You cant beat a turbo, no cubic inches, no other blower. You hear people bitch about lag all the time, most of whom are bitchin are supercahrger guys. If you dont have turbo lag, you dont have a big enough turbo:) I have been running 4 cylinder's for the last 7 years. I run a gt35r on a 122 cubic inch motor, drive it every day to and from work (120 miles round trip) and get 28 mpg.

I am in the process of building a 63 grand sport corvette, its going to be a small block motor (408-427) and will not have anything smaller than a 101 mm turbo.

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Turbovert here in akron aka Mike went 9.20s on pump gas,single turbo SBF and 8.90's with a race gas tune and out of gear.. not sure his mileages but He drove it to Norwalk from AKron 60+ MILES ONE WAY WITH NO ISSUES i say with efi possibilities are endless
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Guest ihuntv8

Yes turbo vert is a perfect example, cubic inch displacement, doubles at WOT. And you still have the driveabilty of a small cube motor.

NOS would be my second choice for a power adder, or just use both:)

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When building a fast car, who cares about gas mileage? First figure out how fast you want to go! You cant beat a turbo, no cubic inches, no other blower. You hear people bitch about lag all the time, most of whom are bitchin are supercahrger guys. If you dont have turbo lag, you dont have a big enough turbo:) I have been running 4 cylinder's for the last 7 years. I run a gt35r on a 122 cubic inch motor, drive it every day to and from work (120 miles round trip) and get 28 mpg.

I am in the process of building a 63 grand sport corvette, its going to be a small block motor (408-427) and will not have anything smaller than a 101 mm turbo.

 

:D I am usually the one that doesnt care about gas mileage. The issue here is that I already have a trans am that gets about 9 miles to the gallon, and my truck gets about 14 miles to the gallon. It would be nice not to have to go to a gas station every week! I will be stuck with this damn truck for a while, but I figured I would pic your guys brains.

 

So lets say you have 2 cars that both run 10.1. The first is a 122ci w/ turbo the second is a 554ci V8 n/a. Which one do you pic?

Edit: The turbo traps 150 and the V8 traps 155.

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Streetability should be good on a turbo'd V8. With a turbo, until it spools, you're running all motor. It doesn't restrict the power of the engine.

 

However.. (Forgive me if you know this already.)

 

..with forced induction, it's usually better to run a lower compression with more boost than higher compression with less boost. So a N/A engine will run between 10:1 and 12:1 compression to make good power. But turbo engines will usually run around 8:1. Obviously, everything else being equal, an engine running 8.5:1 compression is going to feel like a dog compared to one running 11:1. So if you're not under boost, the engine will feel weak. That's where the feeling of lag comes from. So how 'laggy' an engine may feel is partly in the build of the internals. Though getting the turbos to spool sooner helps too..

 

..but not with mileage.

 

Turbos and Fuel Injection are a match made in heaven. You can run A/F ratios like a N/A car when you're out of boost, then start dumping fuel when the turbo spools. So you can get reasonable mileage around town. But let your foot get heavy, and the AFRs will drop from an efficient 14:1 or so to as low as 10:1. Boosted tunes will go this rich to cool the charge and help prevent detonation. As you can guess, a turbocharged car that's nice and efficient around town can quickly turn into a gas guzzler.

 

If you're interested in leaning more about engine tuning in a turbocharged environment, I can reccomend some books..

 

And again, if I'm going over stuff you already know, just disregard this and forget I even posted. ;)

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I know about compression ratios. I'm looking more into the feel from a personal standpoint. I know its going to be different from person to person, hell I think my 110 lsa cam feels fine for a daily driver. I was looking to see why the people that run huge blocks like the na power, and why guys like Trent prefer turbos.
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10:1 554 cubic inch motor n/a will trap 130 range.

 

 

122 cubic inch at 9:1 with a turbo will trap 150:)

 

Ok, so he has a sneaky pete on there ;)

 

So if you had two cars that both ran the same quarter mile times wihich one do you pick?

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Guest ihuntv8

Your always going to get different oppinions, and im not trying to hate on other combos.

 

Its hard to get a car that can trap 150 mph and drive it on vacation. In fact its rare, fuel injection and technology with turbos, and standalones are what makes it possible! The OLD saying goes;

Theres no replacement for displacement!!! Which we all know is a crock of shit..lol

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