Drivability blower vs turbos

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Turbo, although ideal is a fab it yourself deal and room/space is an issue.

You can get a bolt on procharger setup that will make 750-1000 HP and be very streetable. That is the direction i'd head...
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I would... but I like the look of turbos better
 
8.1 will work but you're leaving a lot on the table.

You will make more horsepower per lb of boost than you will per point of compression. An all out race car may run very low compression and a very high amount of boost because they are not worried about throttle response with everyday driving. Since you are building a street car you want to move the compression up so it's not such a dog but not so much that you can't run very much boost without adding higher octane fuel.

I've found that a nice area to stay around for a street car is close to 9 to 1 compression. You can play with calculators computing your "Dynamic" compression ratio with expected compression ratio and boost to find where you are happy running on 93 octane. You need to decide how much power you will be happy with on the street on 93 octane vs at the track on race fuel.


Horsepower with engine size and turbos. You can make way more power than you need to run 9s on a smallblock with single or twin turbos. For instance. Let's say you build a 9-1 compression 360. This is a pretty simple motor but you've put good forged parts in it. With decent heads this motor should make around 300 rwhp. Now let's add a little science. Atmospheric pressure is 14.7 lbs. So for every 14.7 lbs of "boost" you are adding one atmospheric pressure. I usually round it to 15lbs to make the numbers easy. Take your 300rwhp 360 motor and add 15lbs of boost. You have now doubled the output and are close to 600rwhp. This is enough power to push a 3200lb car into the 10.teen range at around 130mph. All on 93 octane. If you change to a higher octane fuel for racing and run the boost up to around 20lbs let's look at the numbers. Engine makes 300 rwhp. 15lbs of boost adds 300rwhp so you're adding roughly 20hp per lb of boost. With 20lbs you would be adding 400rwhp to your original 300 NA RWHP so you'd be at 700rwhp. That's easily enough for a mid 9 second pass.

If you build a 9-1 compression 360 based 408 and make around 400rwhp NA you can run the numbers and see you will be easily in the low 9s around 145mph on 15lbs of boost and pump gas.


Turbos: You're turbo sizing is completely dependent on your motor choice and horsepower goals. There are common turbos that people run but even if you pick a size each size will have several variations. Depending on what you are putting this in you may end up running a single simply to make it fit. At the end of the day what you are looking for is CFM. Your motor will require a certain CFM to run NA. You are attempting to increase that so you need a turbo that will push the required CFM at a boost level it is happy with. You need to look at compressor maps and pick a turbo that will suit your build.

Gearing - Don't run such a high gear that the car is sluggish. Turbos do like long pulls but they also like rpm. Figure out how much power you're going to make. Calculate what your trap speed will be. Pick a gear that put's you just under redline on the tire you will be running for the target trap speed. Autos and turbos are made for each other.

You have a lot of research to do but it's not rocket science. I hope I've been able to shed some light on it for you
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I am planning to run 93 with maybe some mix of race in it once in a while, I Plan on doing the power tours and dragweeks.

The car is a 1968 dart 2 door hardtop- fiberglass fenders,hood,bumpers.

I am planning on a 400 base block and then put a 440 crank to make it 451 and hopefully get about 750-800 hp at the rear wheels. hope to go mid nines, maybe even low eights in the quarter. with the single s480 turbo.


The car is going to have no inner fenders, its going to have a cage that goes up to the front for coil overs.


Thanks for your help



here is what I am aiming for--- goes high eights with a 500 inch stroker and a single s480 turbo. :blob: car weighs 3,300 pounds with him in it, and has 4.30s in it, ya I know , high gears....
 

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Indy makes good heads and intakes but stay away from their crate engines we have a friend who bought one of their 605 wedges and he only made 30 passes (full drag car 0 street miles) before the connecting rods broke and when he called Indy they told o well

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tqfastfish said:
I am planning to run 93 with maybe some mix of race in it once in a while, I Plan on doing the power tours and dragweeks.

The car is a 1968 dart 2 door hardtop- fiberglass fenders,hood,bumpers.

I am planning on a 400 base block and then put a 440 crank to make it 451 and hopefully get about 750-800 hp at the rear wheels. hope to go mid nines, maybe even low eights in the quarter. with the single s480 turbo.


The car is going to have no inner fenders, its going to have a cage that goes up to the front for coil overs.


Thanks for your help



here is what I am aiming for--- goes high eights with a 500 inch stroker and a single s480 turbo. :blob: car weighs 3,300 pounds with him in it, and has 4.30s in it, ya I know , high gears....
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A 408 with a single turbo will easily reach your goals. Low 9s on pump. High 8s on better fuel
 
if your gonna have a 500 inch motor id use 2 s480s.. it will spool them just fine.. and id go 9.1 or more if i were you.. with a giant motor like that and a single s480 your backpressure in the manifolds will be triple whats going in the motor.. a good ptc or ucc converter is a must have..

guys are having zero problems spooling single s480 on sub 330 inch motors.. with a good converter spoool wont be a problem..

id get a 3.25-3.50 gear depending on your tire hieght..

if your goals are low 9s then a 340 or a 360 inch would be fine.. a 649 dollar base s475 would work fine to..
 
Can u list the other specs on the car and also "driveability" wat is your idea of driveability like how much noise r u willing to deal with or wat can u live without like radios air conditioning etc

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1968 dart

fiberglass fenders and hood

fully back halved with art Morrison fab 9 rear.

no a/c

I will have a small vintage air heater

I will have a cd player/radio

I will be driving it everyday I can to school about 30 min . (when its not raining of course)
 
Talked this over with my dad last night and he said to go with a supercharger like a procharger because of heat soaking that happens from the bds superchargers. The reason for running a supercharger over a turbo is that with a supercharger u can run a more highway oriented gear like a 3.23 or a 3.53 and still be able to smoke the tires with ease because u don't have to spin the engine so hard to get the boost like u do with a turbocharger.

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I would but I think the pro chargers are ugly, I want it to look good and fast , that hemi would do it nice but,...... about 20k over my budget
 
Your dad has no idea of what he is talking about. Turbos love highway gears. You have to downshift to get rpms up with a supercharger to make boost. A turbo just needs to be loaded. Low rpm drop throttle and will rip the tires off on the street. Just do a little research on U tube. A turbo is the ultimate variable displacement engine. Low boost drives normal and does not use any extra fuel. Superchargers always use extra fuel
 
I am now seriously looking at S475 turbo to replace the Vortech V2 currently in the engine bay. Went to the 1/4 mile drags end of last year and the alternator belt come off and tangled in the blower belt and snapped it. Had a spare that day. Next 1/4 meet recently, belt shredded. No spare that day. Local 1/8 meet belt came off but was undamaged and went right back on and stayed there for the rest of the meet.
Not exactly fuel friendly on the highway either.
Just in the throws of deciding on what to do as far as manifolds are concerned, to get the best performance with the least hassle.

The turbo info here is awesome. Keep it up guys.
 
more control over turbos, more variables you can build in and add, wastegates, BOVs, housings, etc.
 
Jo Diesel said:
Your dad has no idea of what he is talking about. Turbos love highway gears. You have to downshift to get rpms up with a supercharger to make boost. A turbo just needs to be loaded. Low rpm drop throttle and will rip the tires off on the street. Just do a little research on U tube. A turbo is the ultimate variable displacement engine. Low boost drives normal and does not use any extra fuel. Superchargers always use extra fuel
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This just isn't true. I've built, owned and have driven roots, twin screw, and centrifugal blower cars. And while the Procharged cars didn't hit quite as hard as the roots or twin screw cars did off idle or a slow roll, I had boost at just below 2k rpm. There was no downshifting involved, just mash the throttle and boost was still fairly instant. It still comes down how you build it, and how you have it tuned.
 
doogievlg said:
/6 Matt said:
And just what kind of budget does a 12 year old have?
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He's 12? Thought it was his dad I we were talking to

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nope, my dads to technology illiterate to be on here, lol, his words not mine,

I'm building this car completely by myself , money wise. we do everything in house, I have stalked up parts for a couple years now and I already have the engine and we build the engines, paint, body ect, we never usually do but I am for this car, I am funding it by mainly parting out cars or buying a project , building it and selling, to gain some motivation and money for my dart.... don't worry guys..... I have grown up around mopars, my dad used to own a 66 coronet and he dragraces a 1970 and 72 cuda, I am the a body guy,
 
Putting a sn95 Paxton on my Duster. It will be limited to 8psi boost. I already have it but rebuild kit is $500. For my dart I plan on a GT45
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Can use a Kit like this one. But I will piece mine together
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Block huggers like these.
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Carb hat like this with a Speed Demon 750. People on Turbo forum already have this set up and have made 600+ hp on the Dyno
 
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