Tt 408?

based on boosted331's comments in my thread titled 'cheater nitrous', i'm gonna change my plan. don't think it's possible to get kenne bell to make me a custom s/c capable of feeding my 408. rather than be like every other mustang guy out there and use a centrifugal s/c, i was thinking about twin turbo. that would greatly enhance my street drivability over a supercharger, and would make my 'stang stand out just that much more from the crowd. i mean how many TT notchbacks do you really see out there? especially in the detroit area where i live, which is rife with rice and everybody + their grandma uses nitrous and centrifugal s/c's.

What about a big single? They are cheaper, less moving parts, spool quicker, and will produce the same power.

sometimes the cheaper way isn't always the best way. even in cases like this.

i haven't researched it in-depth yet, but it seems to me that twin turbo would be more street drivable, given that it takes longer to spool. especially in a 6-speed where controlling torque is important, having less to begin with on the street would be nicer. besides, twin turbo hoods look sweet!

anyway, nothing's definite yet. i've come across some sources i can use to research this. i dont' know how many turbo gurus there are here, but any input is appreciated.

If you're going twins, I would run a pair of precision PT61's .81 or .96 A/R tang housings, if you're going single I would run NO SMALLER than a "small frame" PT88. A single T4 housing, even something like a T76-GTS would be severly restrictive on something like a 408 which flows a ton of air. If you don't care about PS or AC i'd do a mid-frame PT88 (uses a TV housing and flange, the small frame uses a T4 flange but a much larger housing and wheel than a standard T4 turbo) with a full 5" downpipe, it would make some decent power :D

Also, FWIW, for a turbo setup i'd go smaller than 408 inches if you want a street car. Any 302-347" motor with a PT76-GTS will be making full boost not long after 3000 RPM's, you could easily squeeze 700+ to the ground out of it on pumpgas (look at brent, 770 to the wheels spinning it to 5000 with 18 pounds of boost on a 302" engine!) but the turbo will push enough air for 900+ on race gas. Using the 8.2 deck 302 just makes it easier to get it in there, easier to buy parts for it, etc.

well, i'd love to take your advice on engine size into account, but my crank just came in the mail today and the block is already .030 over =D. i'm committed. so, i'll just stick with what i got.

i'm not too concerned with lag. it'll be fast enough for me. and more street drivable too, with the 6-speed. i like the idea of twin turbo more than anything else, and it looks killer.

being that this is a street car, it will have power steering, so i might go with 2 independant turbos, if that's possible. one on each side of the engine, with 2 inlet pipes feeding the motor.

i'm not well versed in turbo function just yet. at the moment i'm learning the fundamentals of compressor maps and such. what exactly is a downpipe, and what does it do? should i have a boost controller on this thing so i can run pumpgas on the steet and race gas on the strip? what about inter/aftercoolers?

oh yeah... given my entirely forged bottom end, my block shouldn't have any problems with this amout of power. should i add a girdle just to be safe? how about a windage tray? finally, what would be my best option as far as oil pumps/pickups go? thanks.

a girdle is always a good idea when adding serious power to an engine. ive heard different stories however about running windage trays w/ or w/o a girdle though so look into it. d.s.s. offers a nice 5.0 main support package for a good price.

what year and vehicle is the 351W block from?

i'm not well versed in turbo function just yet. at the moment i'm learning the fundamentals of compressor maps and such. what exactly is a downpipe, and what does it do? should i have a boost controller on this thing so i can run pumpgas on the steet and race gas on the strip? what about inter/aftercoolers?



A downpipe connects to the exhaust outlet on the turbo, and then runs down to your H/X-pipe, or simply dumps. A boost controller, especially an electronic one, is a very good choice. A good EBC will keep boost pressure from reaching the wastegate untill full boost is reached, allowing as much exhaust energy as possible to the turbine(s), which results in quicker spool up. It's also nice to be able to adjust boost on the fly. Charge air coolers are usually called intercoolers, although the proper name is aftercooler. An intercooler is used on a multiple turbo diesel setup, where one turbo feeds into another. An intercooler is a charge air cooler placed between the outlet of one turbo and the inlet of another. Check out This Thread (http://www.ls1tech.com/forums/showthread.php?t=133423) about a group purchase on bigass griffin intercoolers, might want to act fast!

oh yeah... given my entirely forged bottom end, my block shouldn't have any problems with this amout of power. should i add a girdle just to be safe? how about a windage tray? finally, what would be my best option as far as oil pumps/pickups go? thanks.

The ability of your block to handle power has a lot more to do with the actual strength of the block itself, rather than the internals. I talk to TONS of people that tell me "Oh yeah, I got a forged crank, rods, and pistons along with a girdle in my stock 5.0 block, it'll handle 700 RWHP easy" but that really isn't true. The 351W block is a lot beefier than the stock 302 block, but past 600 RWHP and it starts to become a ticking timebomb, unless you've filled it. The only thing i've ever seen a girdle do is keep all the mains together when the block splits in half, a windage tray will free up some horsepower, and make the motor rev snappier because it isn't fighting off as much resistance from the oil.

so if you're running independant twins, wouldn't it make sense to have a separate downpipe for each turbine? and another question, where am i gonna get intake manifolds to fit a system like this? what about a blowoff valve?

Girddles are a waste of money.

5" downpipe, holly shit that is big.


StangNut86,

With a 408, and a TT set up you are going to have a lot of power, maybe even too much. The volume of air needed for this engine is going to be huge, I mean your power goals are very reachable with the combo that you want, but the engine being streetable might be in jeopardy.

Can you list everything that you have for the car? And what you are trying to achieve? 1/4 mile goals? Suspension?

the block is from a '79 Ford truck, that's all i know. it's a 2-bolt main. of course, the main caps are the beefiest i've ever seen on a motor this size.

boosted, you mentioned filling. i've never heard of this before. what exactly does it entail, and about how much can i expect to pay for it?

so if you're running independant twins, wouldn't it make sense to have a separate downpipe for each turbine? and another question, where am i gonna get intake manifolds to fit a system like this? what about a blowoff valve?

Yes, you will have two seperate downs. Your intake options are pretty limited. To me only one option really, go with a Spyder from coast high.

79s are pretty good blocks, but since your going to be putting a small furtune into this engine, why not try and going with a better block. That block will be the weakest link.

What fuel system do you have lined up for this beast? What ECU controller? What injectors are you looking at? What gears are you wanting?

OK I have a question here?

With a 408 and TT set up, your going to have tons or torque and hp at a relatively low rpm. So there is really no need to run a real steep gear. So I'm assuming your thinking of running 3.55's or 3.73's. Because anything more then that and you'll just be smoking the tires no matter how easy you drive. So with that said, what would the point of a 6-speed be?

I can see a 6-speed being beneficial if you had very steep gears like 4.30's or 4.56's on an NA car that made its main power high in the rpm band, and still wanted it to be street friendly.

It just doesn't make much sense to me, what am I not getting here?

StangNut86,

From what you have mentioned. You have the 408 crank. Why not get your power from a bottle? Boosting is not truely ideal for what you are planning, at least IMHO.

You will have plenty of torque for the lower revs, plus if you want the extra power, its there at a push of the button.

What you are planning, the whole package will not work. I mean,yes it will work, but you could spend less money with a different combonation of parts and make a better car.

StangNut86,

From what you have mentioned. You have the 408 crank. Why not get your power from a bottle? Boosting is not truely ideal for what you are planning, at least IMHO.

You will have plenty of torque for the lower revs, plus if you want the extra power, its there at a push of the button.

What you are planning, the whole package will not work. I mean,yes it will work, but you could spend less money with a different combonation of parts and make a better car.

Which is why I sugested a centrifugal blower :iceslolan Looking on the major mustang websites you can pick up a bare YS-trim or Novi2K kit for pretty damn cheap (under 3K) you'll only really need to adjust the mounting bracket and you'll be set, and it will make a boatload of power. Building a turbo kit for a 351W can be a big pain in the ass routing downpipes and trying to get the headers to fit. If you went with a blower, you could pick up a set of swap headers, drop motor mounts, and be done with it.

Which is why I sugested a centrifugal blower :iceslolan Looking on the major mustang websites you can pick up a bare YS-trim or Novi2K kit for pretty damn cheap (under 3K) you'll only really need to adjust the mounting bracket and you'll be set, and it will make a boatload of power. Building a turbo kit for a 351W can be a big pain in the ass routing downpipes and trying to get the headers to fit. If you went with a blower, you could pick up a set of swap headers, drop motor mounts, and be done with it.

Yep :iceslolan

I'm gonna defend main supports(girldes) for a minute. The weakest part of the stock 302/351W and most blocks are the main webbing. That would refer to what you bolt the main caps into. A main support will help to spread the forces throughout the blocks entire main webbing. This does not make an invincible block but does help a nice amount for a real strong street/strip combo on a stock block, hp varying per block type. But in no way does it make a stock 302 block 700HP ready.


StangNut I think you taked something about this motor a long time ago and I said then I wouldn't do a thing until I had a FMS or Dart 351W block. I'm saying the same a 408 with FI threw S/C, TT, ST whatever is not even a good idea to toy with without an aftermarket block cause like Boosted said it is a ticking time bomb. Have you ever driven a Fox with a 408 in it.... If you have't I suggest building a nice N/A 408 and drive that for a while and decide then if you really need to FI that car. A 408TT is not a street/strip car. It's a strip car that's all it is or will ever be and a strip car starts with an aftermarket block.

you guys are right. especially GTStang. i've never driven a fast car before, forget an FI 408. so fuck it. i'll just throw hi c/r pistons (10.5:1) in it and run it n/a. it's not worth my trouble to run power adders. that'll at least keep my block intact longer and keep the car steetable. besides sparing assloads of cash to fix the suspension with =D

a friend of mine has an '86 GT with a 351. i don't even think it's stroked, and if it is it's at 393. he's gonna run the AFR 185s, and that's a route i wanna follow. i need to figure out my airflow numbers and make sure those heads will supply enough. even if they don't, i can port 'em out a bit and make it work. thanks for your help, guys.

AFR 185's are not big enough for a 408. You want something with atleast 200CC's of intake port. If I were in your shoes I'd run a set of CNC ported AFR 205's or 225's. I have a fried with a 408, 10:1 compression, CNC AFR 205's, a super victor intake, 1000 CFM 4150, a fairly hefty solid roller and a little bit of juice. He has gone low 10's @ 130 ON MOTOR, and 9.8's @ 140 on juice, still on 94 octane. That's enough power to annihilate pretty much anything that runs around on the street.

I think your making a very wise choice Stangnut. Don't get me wrong when we all started we had the urge to build a car that will set the world on fire but in the end it's just too much $$$ and it becomes a trailor queen and ya driving a geo metro everyday instead of ya Stang.(Barring you uber rich).

Here is the thing with 351W stroker motors. They are pushing big cubes airflow and trying to get it through small block heads. As far as heads I ran AFR 225's P&P by TEA. You can see even with those heads during my engine dyno that my heads were starting to choke the engine at 6,500pms+. I'm not telling you this to get race heads or AFR 225's cause I barely ever had my car above 5,000rpms on the street cause it wasn't needed, only at that track i went to 7,000rpms. But with 10.5 CR pistons which is a good N/A choice don't go higher you should really get at least AFR 205's so you will breathe ok at at least to 5,500. AFR 185's are a tad to small.

Even with a N/A 408 your gonna need suspension and tranny work.

heh, i dont' have a tranny which will suit that motor. nearest i got is a t-5 out of a 4-banger (my parts car). i'll probably rebuild it with a g-force kit and get a bellhousing from a guy i know who works for Ford. could go with my origional t-56 plan, but that's not looking very practical.

suspension-wise, i'll use the stock stuff out of a junked 5.0. i can get it from a local junkyard cheap if i pull it myself. that'll support the weight adequately, give me an 8.8 rear end to build up, and keep the car drivable while i save money for real suspension (steeda drag race + coilovers, subframes, etc). i just read the article on eaton's new e-locker in MMFF, and i do believe i'll go that route (eventually)

from what i understand, 1-3/4 headers will do nicely. bassani x-pipe and maybe mac or dynomax straight-throughs. eventually it will have cutouts. i might use the GT-40 lower and Cobra upper intakes. the lower i can get cheaply from that ford guy (off his car). the upper can be had easily enough. i say cobra because you can port them more than GT-40 uppers. of course, i will probably end up with an edelbrock EFI deal or perhaps holley. motor will be SEFI by the way. o yeah, where should i get my computer from? i know there are companies who will burn a custom unit, i just dont' know who. might not even need custom.

thanks again guys

I would stay clear of any Ford intake manifold if your running a 408 with AFR225's. I think Edelbrock's Victor or even a Spider intake might be better.

Even with a 408, I would only go with a Spyder intake. It will match the engine a lot better than any other intake on the market.

Yes, you will need a custome chip. Either go with a Tweecer, or a dyno tune to get the most out of the combo.

The normal ECU is not ment to meter a 408ci engine.