Stock block turbo guys?

I ran an incon twin turbo kit for years and tens of thousands of miles at 9.5-10 psi. I ran GT40X heads, and a GT40 intake, stock cam, 30 lbs injectors (yeah, yeah... they're apparently too small... Somehow they did fine), the car ran great. I shifted around 5000 rpm, and it idled and sounded like stock. It made about 420 rwhp and closer to 500 rwtq. Best time I managed at 9 psi was 12.21@118mph with a 2.0 60'. The car was on road-racing suspension, because I used to run it at road atlanta and Putnam Park with the porsche club of america. So, needless to say, it didn't launch worth a damn.

Chris

you can run more than 8psi thru it, gotta be a good tune. right now I run 12 psi, untuned and rich. just got done with it. no problems so far. . lots of people run a lot more than 8psi on stock block.

The E Cam is not a very good choice, the F is a much more Boost friendly cam...

302GTS said:

A local tuner is GREAT with fabbing up turbo kits for stock block 5.0s. He wants me to set one up, and I'll run through his setup and try not to forget anything.
255lph fuel pump
42# injectors with Lightning MAF
Garrett T3 turbo
Custom intercooler
E303 cam
3.55 gears
I BELIEVE that's all he puts in it, mod wise. On bolt-on 5.0s he's gotten a consistent and reliable ~400rwhp out of this setup, running between 8-10 psi. He sets an EXTREMELY conservative tune, and says that the stock block/internals have always been fine with the kit. Hope this helps, and if you need to know anything about what this tuner does, shoot me a PM and I'll be happy to send you some information for him so you can talk with him personally.

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A safe tune will not prevent a split block, but it will help to prevent damage to the pistons and rods.

Splitting the block happens when you make more power than it has the integrity to withstand. I've been told that it is more likely to happen at higher rpms, though I cannot personally verify that information. What I can verify is that stock mains (even girdled) are not stout enough to handle anything over 7000 rpm reliably. In fact, even with a fully built, and girdled Ford Sportsman block, Marc Arnold still experienced main-cap walk at 7200 rpm.

So, even with an excellent valvetrain knowledgeable engine builders recommend that you shift a stock blocker street car at 6500 rpm or lower.

IMO, a safe boost friendly tune will have a target AFR in the 11.5-12.2 range. I'm still tuning mine so I have a very conservative total timing at 18*. More aggressive tuners will push total timing into the mid 20s. However, I'm not sure how much more aggressive a low boost application can go. To do it right, it should be done on a dyno where everything can be monitored closely from one run to the next.

Good luck,

Chris

Stock 302 re ringed, h/c/i 1 year of up to 17 psi from a s trim, 1 1/2 years of 12-15 psi of 72mm.

why in the world would you need an fmu?

Oh and saying that a stock block can handle 12 psi but not 8psi or whatever kind of arguement is a very DUMB statement.. they don't understand that 12psi of boost out of a small t3 flanged gt28 is a lot different than a t4 flanged gt4294.. it's all about volume not psi..

stock blocks have been proven to make 680+ but that doesn't mean they'll last at that power level.. pushing a stock block at more than 500whp for a long period of time at high rpms will lead to splitting the block. they're just not made for that kind of power.

lincoln+ford said:

If i dont plan to run megasquirt.I was going to run a fmu .Is there a cheap alternative way other then standalone/burnt chips?Or w/e the hell they do with mass air 5.0's.

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yeah you have an a9l computer? 42lb injectors, 255lph walbro, adjustable fuel pressure regulator with vacuum advance.. Simply lock the timing.. yank the little spout out and it'll dead lock the timing, so it wont advance with the rpms and than set your fuel pressure.. it'll advance 1:1 for every pound of boost it sees it'll increase your fuel pressure 1 pound.

it'll be fine like that. you don't really need to do much more.. you may want to save up for a standalone in the future but that's all you NEED to tune a turbo fox.

lincoln+ford,

Not to insult your intelligence, but do you understand the difference between a stand-alone and a piggy-back system? Most "burned chips" are piggybacks, which do not replace the stock computer. Instead, these "chips" only give the user the ability to modify the programming in the stock computer. Stand-alones replace the stock computer hardware completely.

This has little to do with FMUs. The only relevance is that at some point before we had the ability to modify the tune in the computer, people would use FMUs to give the car additional fuel. FMUs are essentially boost-sensitive fuel pressure regulators (FPRs) that multiply the fuel pressure based on boost pressure. A 4:1 FMU would provide 4 extra psi of fuel pressure for each additional psi of boost (psig). Adding fuel pressure in this way circumvents the need to tune using the computer. It's a relatively crude method, but it has been used effectively in a lot of tunes. FMUs can also help to make up for injectors that are smaller than they should be. Negative side effects of FMUs include the large strain they place on fuel pumps and inadequacy in tuning the entire powerband. Imagine running 10psi of boost with a 4:1 FMU. The FMU attempts to compensate by adding 40 psi of fuel pressure! Now your fuel pressure is a stratospheric 80psi, and even a high-pressure walbro will struggle to move adequate fuel for a high hp application: Walbro Fuel Pump Flow Figures Additionally, absurdly high fuel pressures can cause injectors to go static.

If you can electronically control the tune, and you have injectors sized correctly, there is no need for an FMU. Whether you have a stand-alone like the megasquirt, F.A.S.T., BS3, or AEM or a piggy back like the EEC-Tuner, Tweecer, or Quarterhorse. If you can electronically control the tune, then you should be able to more accurately tune to all engine rpms and loads, and you'll be able to do it without unnecessarily high fuel pressures.

Don't waste money on 2-gallons of race gas per tank. If you're confident in your tuner, there is no need for this expensive insurance. It would just be a waste of money. Tune conservatively and drive confidently. If your tune is safe, your motor will be.

Chris

347_stang said:

yeah you have an a9l computer? 42lb injectors, 255lph walbro, adjustable fuel pressure regulator with vacuum advance.. Simply lock the timing.. yank the little spout out and it'll dead lock the timing, so it wont advance with the rpms and than set your fuel pressure.. it'll advance 1:1 for every pound of boost it sees it'll increase your fuel pressure 1 pound.

it'll be fine like that. you don't really need to do much more.. you may want to save up for a standalone in the future but that's all you NEED to tune a turbo fox.

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If you're going to do this, lock the timing at something conservative like 18*, not the stock 10*.

The boost sensitive FPR is necessary because is keeps the pressure drop across the injectors constant when boost increases. Without it, the added pressure on the intake-side of the injector would slow the rate of fuel through it. For example, can you imagine how little fuel would be injected on my car at 30psi of boost? Without increasing the initial baseline fuel pressure (mine's at 50psi), there would only be a 20psi drop across the injector (50psi FP - 30psi boost = 20psi drop across the injector).

Running a car like this is not even close to an ideal solution. In fact, it's probably worse than using an FMU, because at least running rich will prevent detonation under boost. While the car would run, without tuning the fuel curve or watching a wide-band, you're pissing into the wind without any of idea of the wind's direction and speed. Iraqi fighters used to hold their AKs over ledges without exposing themselves and they'd empty an entire clip at us from 100-150m away. We called it the spray and pray method. Sometimes they get lucky, but not usually. If you're going to attempt this without any ability to tune the fuel curve at all, at least take a look at the AFR once on a dyno to make sure it's not running lean under boost.

Chris

I know it's not ideal.. but he said cheap.. that's about as cheap as it comes lol..

I personally have a wideband so I can monitor my afr.. I plan on at the very least getting some sort of piggy back chip so I can have better driveability when not in boost.. but we'll see how it goes for the time being.

at the moment everything is set very conservatively so as to not run too lean.