ok, firstly, im not some pimply assed teenage timewaster that knows nothing about cars, ive been drag racing for years, just new to turbo's, so save the stupid comments.


im thinking of building a true street car that runs on pump fuel NOT E85, something that the mrs can take to the shops or jump in and drive for 300 miles blah, blah blah, you get the picture.

the car im looking at is an Aussie Ford Falcon EB XR8 (think 4 door 92 Mustang), these come standard with a roller cammed efi Windsor and a BTR 4 speed auto. they weigh 3300 lbs and im thinking thats what it will weigh after the install ( i will be removing unwanted junk), this car must retain air con and power steer and run a low 9 second pass with ET Streets or equivilent.

what needs to be done to make this happen? is it acheivable or am i wasting my time?

im fairly certain it can be done without spending heaps of cash and i think this is the best place to ask.

thanks in advance. Justin.

 

how much money is in the budget?
9s should be easy with 3300lbs of car. also the beauty of turbo cars is that they are completely drivable on the street since all their power comes when only in boost and dont act like a heavy cammed or nitrous engine thats rough on the street. i daily drive my twin turbo GTO or you would know it as a HSV coupe gto with no issues other than the speed limits.

as for power i would say around 750rwhp for a light setup or round 850-900rwhp should do the trick for a 9 sec. pass but it all depends on the final weight plus gear setup.

 

Can the 5.0 block handle that power?

Need to spend some money on the setup but its doable on pump gas. Go for the biggest cubes you can get to keep boost levels down. My 401 chevy made 640whp on mustang dyno at 12.5 psi. At 14psi it ran 9.8's at 140-141 mph in good air and thats with no real launch. I anticipate another 3 tenths in this setup with a boosted launch once i get my converter issue fixed. Thats 9.5's with a mild setup in a 3500 lb car or so with me in it. Might be heavier I'm not sure

3300 lb and 700whp should easily do your goals

 

i dont think that the stock 5 liter block will handle it, I know the American block wouldnt do it. I dont know if you guys use the same block over there.

 

This is good advise for street performance as it means better response but unfortunatly it is more exspensive.

The cheapest route to big power with a turbo is an engine with modest N/A power. An engine that only makes around 400Hp N/A will make big numbers with a single T4 running a lot of boost. Anything more and you must jump to two T4s or a T6 and either one of these options make keeping all power accessories tough. It can be done but it costs more.

 

thanks guys,

the blocks we use are the same as yours, so i wont be using a standard block.
347 cube svo block might be the go then.

what about heads? do i have to use exotic stuff or will gt 40 heads do the trick? or just go and buy AFR's?

 

Ported GT40s can perform fine but they have thin decks and it is too easy to spit out a gasket running a lot of boost. Get a set of AFRs.

 

thanks Andy.

 

Not sure if this helps or not but I'm building a 331 stroker with an twin Incon 800 kit. I will be running it on E85 (I know you want pump but that's what I'm running). I am hoping to run somewhere in the 9.2-9.4 range with it. The car should be about 3300 lbs with me in it when done. You could always do two small turbos like the Incon for quicker spooling and maybe a little better drivability.

Just my two pennies.

 

Please explain your reasoning why twins will spool quicker and give better driveability than a single. A properly sized single will perform the same as a properly sized set of twins.

 

Nine second turbo pump gas cars certainly exist. I personally know an individual who had a car well into the 8's that was also driven 25-30 miles each way to a local cruise pretty regularly. This was a BBC based car with small twins in a tubbed car and the 8's came on better gas.

There are plenty of variables but I'll make the following assertions...

* Getting where you want to be is largly a function of avoiding detonation.
* The more displacement you have the easier it will be to get there on pump gas. More displacement means that a given HP level can be reached at lower RPM and boost levels.
* In my opinion DFI and quality tuning makes avoiding detination easier due to more precise A/F management throughout the range... *

Like I said - there are many different ways to go nines - if you are Bill Gates you can go to Nelson Racing Engines or someone like them and buy a $50,000 "crate engine" turbo setup that will make 1100 HP at the wheels on pump gas.

On the other hand if you are poor and crafty - I suspect you could go to the junkyard, pick up a low compression 460, add good rod bolts, slap a couple of $300 58mm industrial T4s on it with Megasquirt or a blowthrough prepped carb, run 91 octane pump gas, alky or water injection, and have the power to get into the nines until something breaks. You might be surprised how long it can last if you avoid detonation and keep RPM in check.

There is all kinds of stuff in between these option.

 

thanks guys, these are all great options, BUT, I HAVE to use a 302 based block and i HAVE to use the stck STYLE efi to keep it road legal in Australia.

 

Still "doable" but will not fall in the realm of "cheap" by any stretch of the imagination. I can't see you getting there (low 9's) on a stock block based build - but it wouldn't be the first time someone made me eat my words. Constraining yourself to < 350 in^2 means a bunch more RPM and boost to get to your goal...

 

Why do you have to use a 302 block? A 351w block or aftermarket version will look nearly identical. I don't know about your emissions regulations over there but most mustang guys don't spot the difference on a 302 vs 351 especially with efi and all the belt driven accessories up front.
Cubes is king when it comes to pump gas power!

 

Inertia of the compressor and turbine wheel obviously has a large impact on spool time and it turns out that if all else is equal two small turbos with an equivalent rating to one large turbo will have less inertia than that one turbo thus spooling faster.

 

point taken, the idiots that check the cars wouldnt know what they are looking at anyway..........

 

Makes sense but also have half the motor going to the smaller turbo so the ratio might be the same...that is the exhaust gas mechanical/kinetic energy required to overcome the rotor inertia for one smaller turbo with half the motor vs all the exhaust gas energy on one larger turbo. Hard to say without actually calculating the inertias and exhaust energy created by each bank.

Twins are smaller so its nice to package them in the engine bay plus they look cooler than just one large turbo.

 

Thats what I am thinking as well. Twins use half the exhaust energy to move a smaller wheel vs. a single using both exhaust banks to move a bigger wheel. The single wouldn't be double the size or weight of the twins so it could and should be more responsive (in theory). I am fairly new to turbo's but a motor set up with say twin 70's wouldn't run a 140mm turbo to make the same power. So shouldn't the single be more effecient.

 

The cross sectional area of a turbo is more or less what dictates the HP rating. Since cross sectional area is exponential you can't just say twin 70's is the same as a single 140. A single 140 has way more HP potential.

 

Yep just like exhaust sizing. dual 2.5" is about same as 3.5" single in flow capability because area is about the same. Compressor wheel flow capability is greatly affected by wheel diameter and blade profile. Larger diameter wheel can pass more air, but 2 wheels of half diameter dont add up to 1 wheel of full diameter