building a motor for a turbo??

[lightngsvt]

With all this turbo talk, I am seriously leaning that way (now that a kit will be available). But what I need to know is how different would I build my motor for a turbo, compared to a N/A + nitrous setup? What about cam specs?

I was leaning toward a long-rod 357 (.030 overbore), +/- 10:1 comp with good foreged piston, h-beams rods and "worked" stock crank. I have mildly ported Edelbrock heads and planned to keep the GT40 intake system. Im also using full bassani exhaust setup. What would I need to do different? And would it be bad to run a turbo motor N/A or with nitrous until the turbo kit becomes available? My goal would be low 12's - high 11's with a turbo, about 8-9 psi of boost and to be able to run on pump gas. Oh and I do have an EEC-tuner from Raymond too. Thanks for the input guys!

 

[FMOS Racing]

Chuck,

If you're going to put together a motor, get the compression down to around 8.5:1 and you'll be able to run more boost safely. And to maximize the combo you'll want a custom turbo cam - but that's easy enough. Turbo cams tend to drag the intake opening until well after the exhaust valve is closed.

It won't be BAD to run the motor N/A or with nitrous, but it won't be as powerful as a combo built to be N/A or nitrous. Won't hurt anything, though.

One of the beautiful things about a turbo motor vs a supercharged one is that because the turbo doesn't require the mechanical interface, you get more power per pound of boost. So, if an engine is making 500 hp at 10 psi with a S-Trim, it'll be making around 570 hp at 10 psi with a similarly heat-efficient turbo setup. And that 570 hp comes at the same cylinder pressure as the 500 hp did, so the engine itself isn't working any harder, only using more of its power to turn the wheels.

That's the plus side of the turbo equation - they're more efficient. That's their payback for being more expensive and more difficult to install and requiring more maintenance (they're tough on the oil and produce a good deal of heat) when compared to superchargers.

 

[lightngsvt]

I figure an 11.90 pass would take about 112 - 114 mph and around 500 - 520hp. Am I close? From what you were saying about Mikes kits, this should be a easy goal, even without an intercooler. And 500hp would make me very happy! I still want to be able to turn 13's N/A on motor. Would you think something along the lines of 8.8:1, or even 9:1 with forged pistons and say 6-8 psi of boost would be reliable and still make the 500hp + goal?

I already have the exhaust, heads, ignition, EEC-tuner, injectors and ported intakes. All I would need would be fuel system upgrades, cam Motion cam, the turbo kit and dyno time. These kits are a for sure deal?

 

[Lightning Ralph]

Go TURBO!!!

I belive you must have low Compression like 8.1 & a Good Turbo Cam. (Mine is a Comp Cams .600 Lift) I was told that once a Turbo System is Dialed in & is making optimum Power the only thing left to do is Change Oil more frequently than Normal Because the Turbo Car's & Truck's tear it up alot Faster than a SuperCharged Car Or Truck.
Just like Jeff said also the Exhaust Spins the TURBO which is not a Restrition to Horse Power. If you take a (T-88) Turbo making 1,000 H.P. than Changing it to a ProCharger D3M it is possible to lose 100 H.P.with the same Boost.... Turbo's get Free Exhaust Flow H.P. .....SuperCharged Car's need to turn the Blower Belt to make the H.P.!!! The Belt Robs the SuperCharger of H.P. because it is a restriction...I hope I explained that where it makes some sense....


Ralph Voorhees Jr.
93' Red
NLOC 330
Turbonetics (T-91) Big Thumper Turbo
383 Race Stroker
Tubbed & Back-Halfed
Goal: 9.0's @ 150+ MPH
"Pull The Chute"!!!!

 

[HouseofSpeed]

Don't even consider turbocharging anything without an intercooler....its not an option on a turbo car if you want to get the most out of the combo.

For an example of that, look no further than the progression of the Buick turbo cars....NO ONE wants a hot-air car (84-85), and the first thing most do to a hot air car is add an intercooler.

I am more of a fan of running some compression and dropping the boost on a street driven setup. 9-1 and 7psi makes for a nice combination given the proper heat exchange unit and proper tuning.

Cam selection and torque converter selection are critical....0 overlap or even "negative" overlap as Jeff mentioned will make for a responsive car with the proper converter. I am thinking at least a 2800 with a single of any measure...probably more like a 3000. You will also play with lock-up as well, a lock-up is worth 1-3 mph at the top of track over a non-lock setup.

Spend your money on the intercooler and the fuel management...then sit back and enjoy the ride.

 

[Lightning Struck]

There's really no "black art" to building a turbo car. If you look over on the corral, there's a bunch of people running 12's,11's, and even 10's on a STOCK motor.. Stock block, stock heads, stock intake, STOCK CAM!! They have found that the stock 5.0HO cam is actually a pretty good turbo cam. With that being said here's what I would do as far as a combo..

Since you have aluminum heads, stay with stock compression(8.8:1) this will be fine for a turbo an aluminum heads. Figure out what you want to be ABLE to run as far as boost, this will have alot to do with what you run for a fuel system. I don't agree with a 3000RPM stall converter however.. I would run a PI 2400 stall convertor, because with the extra torque you have on tap that stall will be alittle higher because you'll "sheer" the fluid. Give Terry a call at Cam Motion, or even Ed Curtis at TFI.

USE THAT TUNER!! You'll want someone who's good with turbo's to do the tuning, there's little tricks ya can do to make it run like a raped ape. Remember, you'll be getting ALOT of extra down low torque with a turbo, from the mere fact that you'll see maximum boost at your torque peak(highest load=highest boost). This causes a real strain on the fuel system and timing computer..

This is going to surprise alot of people, I would switch to 3.73 gears. You can keep the 4:10's, but you won't need to rev the motor to the moon at the top end of the track.. I would say you should be going through the traps at less than 6 grand, probably closer to 5-5500RPM..

Depending on the size of the turbo you go with you'll see a fair amount of boost at 2500RPM, that's why I don't think you'll want a 3000RPM stall, you want it to lock up(stall wise) and put that extra load on the motor to get the boost to build quickly..

And with turbo's traction is paramount, if you're spinning you ain't building much boost.. Alot of guys with turbo's that normally build 14 psi right off the bat, will see maybe 4 psi if they spin out of the whole..

So really a turbo motor is a conservative motor. You're trying to maximize exhaust velocity.. I've heard of Supra's running 1 3/8 exhaust trying to up the velocity(and heat) in the headers to try to minimize lag, and build more boost.. That's the one downfall of a single turbo on a V-8, you have to pipe all that exhaust gas around the motor to the turbo.

My plans for a turbo motor are a 393, TFS heads, Cam Motion Roller cam, 8-8.5:1 compression, Eagle Rods(sounds like someone elses motor.....JEFF!) and right now I'm working out the fuel system and engine computer situation...I'm trying to convert to mass air(VEX1) but am having some troubles find the hardware.. I know I can do the conversion, just need the computer and a mass air truck harness to butcher..

Any more questions??

 

[Thundrn_Lightning]

My plans for a turbo motor are a 393, TFS heads, Cam Motion Roller cam, 8-8.5:1 compression, Eagle Rods(sounds like someone elses motor.....JEFF!) and right now I'm working out the fuel system and engine computer situation...I'm trying to convert to mass air(VEX1) but am having some troubles find the hardware.. I know I can do the conversion, just need the computer and a mass air truck harness to butcher..

Curt,

The VEX1 PCM part number is F5TF-12A650-HB. It is also listed under F5TZ. I know you want to save a few bucks, but I've found that finding that PCM in a junkyard is virtually impossible. If you do find one, go buy a lottery ticket immediately. The other hardware is pretty easy to get.....let me know if you need help. I also have .pdf files of VEX1 pinouts, diagrams, etc, as well as the stock speed density stuff, if it helps.

This turbo stuff is intriguing, but I will stick to the tried-and-true S-Trim. I still think I can hit my 11.50/120mph goal with a cooler, all the supporting hardware (heads/cam/fuel/etc), and lots of tuning. You turbo guys better post a bunch of pics when you're all done!!!

Later,

 

[Lightning Struck]

Kevin,
You've sent me the pinouts and diagrams before.. I've pretty much come to the conclusion I'll be buying the computer from Ford. It's 255 plus core.

I'm really looking for a mass air harness.. I don't have a part number, or really a place to look. If I can't find a VEX1, then where will I find the harness to make one work?? Or can I splice into the existing harness with a sequential injector part?? I've figured the pins that need to be changed...Just need the injector wires, which I know I can do..

 

[MO351]

Maybe an odd question but what about just routing one header to the turbo? What's the reason behind both headers going to the turbo? That just kinda popped in my mind while I was reading this thread again.

 

[Lightning Struck]

You want to use both headers because you'd be cheating yourself out of alot of boost response with only one header. You want the heat and volume of exhaust to be large. If you only routed one header you'd have alot of lag because you'd have only half the exhaust gases pushing the turbine. So you'd be feeding the turbo with only 4 cylinders...

It's just a really bad idea..

 

[POWERSTROKE]

Yep, Curt's right... The Turbo diesel guys have problems with loose exh. manifold bolts, leaky joints, bad gaskets & stuff. It's amazing how much boost a little leak will cost You with a turbo... A PURE stock '94-'97 Powerstroke normally makes 16-17 PSI of boost. If there's a little leak at the exh. manifold flange or the "Y" pipe they're lucky to get 10-12 PSI. So If You dump half the exh. out the back....... Why bother....

 

[FMOS Racing]

Actually, Saab or Peugot has a "asymmetrical" turbo system on one of their cars. Uses the exhaust from only one side. However, this engine is designed from the outset to be used that way and there's all kinds of tweaking done to the cams, combustion chambers. intake and exhaust ports, etc to make it work reasonably well.

For our applications, it's certainly simpler and more efficient to run a crossover.

 

[lightngsvt]

so there doesn't seem to be a consensus on what is best. I like Kyles idea of running around 9:1 compression and around 7psi of boost. With aluminum heads, would I be able to go higher boost with an intercooler, safely? Anyway 500hp +/- (enough to run an 11.90 on a good run) would be my goal, unlike the 6-700hp some people want. what is the time frame for the turbo kits? What ID like to know if I built a 9:1 motor with a turbo cam (custom from Cam Motion) and all my other add-ons, could I still get say 325-345hp, enough to run 13's, on just the motor? The reason I ask is because it could be 3 - 12+ months after the motor before I could get the turbo on there and I dont want to be to slow in the mean time. How would nitrous be on that sma emotor (before the turbo)? Would an "off the shelf" converter be Ok, or does one need to be completely custom made and "tuned"? What else do I need to address?

 

[Thundrn_Lightning]

Kevin,
You've sent me the pinouts and diagrams before.. I've pretty much come to the conclusion I'll be buying the computer from Ford. It's 255 plus core.

I'm really looking for a mass air harness.. I don't have a part number, or really a place to look. If I can't find a VEX1, then where will I find the harness to make one work?? Or can I splice into the existing harness with a sequential injector part?? I've figured the pins that need to be changed...Just need the injector wires, which I know I can do..

Couple of things - if you get in good with a dealer, you can get a PCM for $180 (10% over cost, I'm told, which is what I paid) plus a $100 core. They were picky about the core - I couldn't give them an Escort core I had lying around.

Anyway, you really don't need to buy a harness. Well, not necessarily. While you can modify the current injector harness, you can also just make up an "overlay" harness that just contains 8 new injector plugs plus the MAF plug. Get the plugs from the junkyard, or possibly they can be had from Autozone. I know they carry the MAF plug, not sure on the injector plugs. Regardless, it won't cost much either way. Then, the cheapest way will be to re-pin the existing truck underhood 60-pin connector to match the VEX1 outputs. And simply add in the leads from the (sequential) injectors and MAF. I'd be glad to talk you through it. If I haven't already I can send a pic of what my overlay harness looks like.....since you seem to be a DIY'er, it should be a peice of cake for you to duplicate.

Have fun,

 

[SVT-FAN]

How about putting a turbo on a stock motor sound to you guy's.With the right fuel and exh.The "L" has 8.8to1 compresson for the factory right??That seems like a good number for boost!Does any one think a stock motor could handel the turbo safely Not saying I plan on doing this but, was just kind of wondering about it and thought someone would have some good reply's about this.

 

[LightningWX]

How about putting a turbo on a stock motor sound to you guy's.With the right fuel and exh.The "L" has 8.8to1 compresson for the factory right??That seems like a good number for boost!Does any one think a stock motor could handel the turbo safely Not saying I plan on doing this but, was just kind of wondering about it and thought someone would have some good reply's about this.

Let me go try it . Whats with all the single turbo talk, I'm behind on my corral reading. Is there some advantage to single over twins? If you have some block hugging headers you can just turn them upside down, make a pipe to put the turbo alittle closer to the front of the truck. Then you can run the exhaust exit right back under the headers to the back of the truck you can stub a K&N off the bottom behind the bumper and you can route the air outlet right to an intercooler in front of the radiator. Single seems like it takes a **** load of tubeing and the exhaust has to travel a long way to get to the turbo. Also, doesn't haveing the exhaust from one side come right out and the other side have to go all the way around the engine goof up the air flow. Wouldn't the goal be to have the least amount of pipeing possible?

 

[Lightning Struck]

Yes the goal is to have the least amount of tubing possible, but it becomes a packaging issue. Unless you want to move all the accessories around, a single is just an easier proposition. Plus there really isn't that much lag...Twins are easier to package on a V-8 IF it wasn't for the front dress...Plus the setup is already tried, mocked up, and being produced..If you want a twin turbo setup, you'll have to make it yourself..

And yes, a stock motor will hold up fine to a turbo...I would just replace the valvesprings, that's all..

 

[FMOS Racing]

How about putting a turbo on a stock motor sound to you guy's.With the right fuel and exh.The "L" has 8.8to1 compresson for the factory right??That seems like a good number for boost!Does any one think a stock motor could handel the turbo safely Not saying I plan on doing this but, was just kind of wondering about it and thought someone would have some good reply's about this.

This was actually covered on the thread titled "turbo" - Mike Arnett made over 500 hp to the rear wheels and ran 11.60s with the turbo kit, Crane 2030 cam, ported stock heads, and a PI converter. That's on 8 lbs of boost.

Chuck, the boost/compression trade-off all comes down to a matter of what you want. If you want to run more boost and make the most power, you drop the compression ratio. If you want the best throttle response and off-boost performance, you raise the compression ratio and give up some boost.

Personally, I'm running a 10:1 motor and will shoot for 6-7 psi on the street with an intercooler. That's pretty equivalent to the 8.8:1 CR of a stock truck with about 11 lbs of boost in terms of dynamic compression ratio. That's very doable on 93 octane and conservative timing.

Another negative to duals, besides packaging, is cost. I'm looking at a $1500 turbo... I'd rather that not be a $3000 pair of turbos. But anything is doable with the proper application of a flame wrench, large hammer, and time and money. And yes, you can get a pair of junkyard turbos and do your own for less than that, but in this case it's a kit.

 

[Lightning Struck]

Actually Jeff, with two small turbos the price wouldn't be THAT different.. A T04B is about $700 a piece, so you'd be right around the same price...But once you figure up the equipment for a twin setup I'm pretty sure you'd be higher.. The big T series turbo's that we're both looking at are just more expensive because they're bigger/better turbo...If we really wanted to spend the dough go dual ball bearings..Which depending when I do this I might perhaps splurge on..

Unless you really get crafty with turbo placement on the passengers side, there's really not a ton of room. I'm sure you could put one somewhere, but all in all, it's alot easier to just put a single on the drivers side front of the motor.. When I looked at the truck and did some measurements and stuff when I was planning on making my own kit, that's where I was going to put it.

 

[POWERSTROKE]

Look at how Ford packaged the turbo on the PowerStroke... Stuffed back in the firewall just to the passenger side of the V at the back of the engine. If You've ever seen a PSD on an engine stand it's really not much different in size than the 351W. With the turbo in THAT location the exh. runs are about as short and direct as they can be without throwing a ton of heat into the engine compartment... but they still put heat shields everywhere, and the exh. outlet on the '94-'97's is almost crushed flat! The downpipe is the #2 hop-up on those trucks! and You have to dent the firewall to fit them in. Really not a great location. If You mount the turbo up front all the piping gets shorter, the turbo gets more cooling airflow and the whole combination runs cooler when in motion.