Newb Turbo Questions...

Discussion in 'Fox 5.0 Mustang Tech' started by Mike85000, Aug 31, 2007.

  1. Hey guys,

    I've been reading up on quite a bit, the turbo bible etc etc.


    I've read somewhere that SD works better for boosted applications. Is this referring to the stock EEC-IV SD i have in my 87 Stang or ??? How does the MAP sensor handle reading boost rather than vacuum? If I were to build a turbo setup with my stock SD EEC would it even run, or is there a lot of modifications to the EFI system required?

    Obviously tuning is very important but from what I have read, MAF stangs will run a turbo without a tune in most cases.

    Also, how does all the vaccuum related equipment work when you are boosting? I mean brakes should still work because when you are on the breaks, you are off the gas = no boost, vacuum. But how does it affect other things like the PCV system and other vaccuum related stuff?

    Here's the list in my head so far of things needed for a turbo setup.

    -Turbos and all the plumbing (oil feed/drains, downpipe, headers etc)
    -Wastegates (best to plumb back into downpipe or to atmosphere? fumes in car?)
    -Intercooler - Air to air for street
    -Upgraded fuel system (pump, injectors, AFPR)
    -BOV (goes before TB or MAF?)
    -Free flowing exhaust system
    -Tweecer R/T or ??

    Probably lots that i am forgetting.

    Thanks in advance for the help.

  2. I can't answer really any of your questions regarding turbo setups because I have absolutely zero experience with them. The one area I can help is that the SD systems they're referring to as being better are more than likely an aftermarket setup like an Accel DFI or FAST system. I don't know if the TwEECer or PMS can tune the factory system.
  3. I have a 92 GT with a Hellion 62 mm turbo. Best money ever spent.

    - I have the stock computer w/tune.
    - MAF is stock, kit came with new bigger tube.
    - If you have duals like I did, you'll have to do single
    - You will need bigger injector's ( mine came with )
    - A few feet of vacuum line
    - A punch to make a hole in the oil pan for drain line
    - Get lots of zip ties, to tie off every vacuum line ( old guy secret )
    As for vacuum, if you had good vacuum before, you should have the same or better after. It doesn't affect it that way. All the other vacuum related accessories will work fine.
    Your PCV? Think of your motor as a glorified air pump, ( witch it is ), it "draws" air, and pumps it through.
    Now with the turbo, when you see boost, your now forcing the air through. If your car had any problems before, they will be heavily amplified now. ( seals that may have been weak, will now blow. If it can find a place to blow oil out, it will. You open up a whole new world.

    But it's all worth it. I'll give you an example. My car

    - 92 GT, Stock bottom end
    -Heads, cam, Intake ( AFR's, no other )
    -All the usual bolt ons.

    My car put down 317 to the wheels, and 321 torque. Thats very respectable for a N/A car.

    Then I put the Hellion kit in. It was complete. I didn't have to buy a single thing. It came with new exhaust, every bolt, every clamp, new injectors, MAF, everything you need.

    You can run the car untuned. All you have to do is set the timing ( Initial ) to 10, and leave the timing pill "Out". This is a little cheat so you can drive the car a bit. You have to keep the boost under 7, and make sure you don't lean out. This is just a temp till you get it tuned.

    After I put the Hellion in, I strapped the car down to a dyno.

    My car made 500 to the wheels, and 560 torque! Untuned!

    The car runs amazing under normal conditions, gets decent gas mileage, and is so very exotic.

    I would recommend buying a complete kit, but if your piecing it together on your own, definitely get someone who's done it before. One mistake ) overboost, detonation ) and you lose your motor.

    Don't run an FMU, they're garbage. Get the tune. You'll thank me later.

    Bigger fuel pump ( 255lph )

    Get a good quality Wideband A/F gauge. This will be the most important gauge you have, even more than the tach. ( you over rev, and you have a rev limiter. You lean out too much under boost, and it's game over. Blown head gasket, or worse ).

    Thats all I can think of right now. I f I think of more, I'll put it up.
  4. Looks like a decent initial write-up. I have to interject on a couple of things though.

    "If you have duals like I did, you'll have to do single"

    Really, Im not quite sure what you mean by this?

    "You can run the car untuned. All you have to do is set the timing ( Initial ) to 10, and leave the timing pill "Out". This is a little cheat so you can drive the car a bit. You have to keep the boost under 7, and make sure you don't lean out. This is just a temp till you get it tuned."

    You do not want to set the initial timing at 10 and pull the spout. Locking the timing at 10 will result in extremely retarded timing not only for regular daily driving, but for full boost apps as well. You will be leaving TONS of h/p on the table as well as running your engine (and all hot parts) extremely hot from the timing. If you want to lock the timing (I've done it in the past before my megasquirt) start off at around 18* for 8lb's of boost and work your way up. I was able to safety run 20 degrees locked total on premium without any hint of detonation and the road manners didn’t suffer to much at all.
  5. Millhouse, is that 18* advanced? I rand 16* advanced without my turbo. Now I just finished puting on my turbo and I am confused. I thought you had to retard the timing under boost?

  6. How did you set the 16* advanced? Did you put the spout connector back in afterwards?
  7. Yes, I pulled the chip out. Set it to 16* advanced by turning the distributor and a timing light. Replaced the chip. Runs like a champ.
  8. Alright, well because the stock timing was set at 10* you basially advanced your timing another 6* beyond stock. When you put the spout back in, the computer takes control back on the timing system and uses the stock timing tables (+ the 6* you advanced it).

    As a quick fix to tuning a turbo you can advance the timing to 18*+ and leave the spout out...efectively locking the timing in place regardless of the computer. This ensures that no matter what bost level your running, you timing will remain in a safe zone so to speak. This is all comes with a price however. While WOT will be close to being optimized (when you advance the timing appropriately) you will leave a small amountof h/p on the table. You will also sacrifise some road manners as the timing will be locked regardless of load.
  9. but is it not true that you want to retard the timing more than stock so as not to cause detonation?
  10. With the method I described, you would in affect be retarding the timing.

    You see, with the base timing set at 10 * and the spout plugged in, the computer will advance the timing an additional 16* at WOT for a total timing of 26*. When you advance the base timing to 16* the computer wil still add 16* at WOT which brings your total up to 32* at WOT.

    Now let's go back to setting the timing at 18* (or more) with the spout left out. Under low loads he timing should be near 32* total...but because it's now locked at 18* your driveability will suffer. When at WOT however you'll still be at 18* which will actually (for WOT) be retarded by 8*.
  11. OH, that makes perfect sense. I forgot all about the computer advancing the timing with the spout pluggeld in. How much do you think drivability will suffer? Is there a way to set it and leave the spout in? Also, I have the crane cam HI-6S and they make the boost-proportional timing retarder that plugs into my module. Would it be better to get that and then set my air/fuel to 14.7 (or close by) or get the tweecer for $280 and mess with that? Thanks

  12. When I was driving with the spout unplugged, driveablility really wasn't that bad. I had to let the car warm up for a couple extra seconds before leaving. Low load acceleration when timing is normall thrown in also is a bit boggy and you'll also loose some economy on the freeway.

    There are some that have had no issues running low boost (~8psi) and retarding the base timing 4*. While WOT will most likely be fine, it's the part throttle/full boost areas that will get you into trouble. It's those areas that the stock computer will still be throwing timing in....right where you don't need it.

    I've never been a fan of those plug in boost retarders. I've heard of way to many horror stories from them failing to even consider it. Any aftermarket or piggyback that will allow you to alter your fuel/timing tables would be a much better route to take.
  13. Which piggyback system would you reccomend. For now would it be ok to drive for a while at 18* without the spout? I am kind of on a limited budget after buying all the turbo stuff. Thanks.

  14. That's really going to be all up to you. I'd do some heavy reading both on the corral and turbomustangs as both have EFI tuning sections with tons of info. I personally only have done the locked timing method along with the jump to a Megasquirt standalone…so I really can't lead you towards a system I'm not familiar with.

    Just keep in mind, if you have your heart set on a bigger better piggyback, standalone or custom dyno tune with chip…you can always try the locked timing method until funds become available. It's never fun buying something to "get you buy" just to upgrade a few months later.
  15. thanks for all the help. Ill start reading so I know what to get when funds are available.

  16. I'm running the HP T60 street kit and on GT40 heads and Cobra intake, spout pulled out @20 degrees I put down 511rwhp 622 ft.lbs trqe.@10psi and no streetability issues. Then I changed to Trick-Flow lower and Hogan upper and I started to feel a little bogging around 2500rpm. nothing I couldn't live with, but I heard about this XPI timing lock unit, so I got one and installed it yesterday I think this is gonna be the best $150.00 I've spent. It maintains factory timing til it sees boost then it locks it where ever you set it. I tried it @ 14 degrees initial and set the lock @ 18, it feels like a different car to drive, alot more aggressive feeling at lower rpm. and no bogging issues.