HotrodTSi Posted June 12, 2004 Report Share Posted June 12, 2004 Well my first dyno run was a flop...help me sort this out. First, I need a place to host my Dyno Scan so you can see the problem. My mods are listed below. I installed a fresh set of NGK BPR7ES's gapped at .035" before I went. My base timing is at 16*BTDC per TimC's advice with the Roller cam. I was having issues with the vacuum advance and MPI...seems that with the constant vacuum signal from the plenum I was gaining about 30*+ with the hose re-attached. I tried a one-way check valve...that did not work, since it kept the boost from retarding the distributor at higher RPM's. Then I tried running the vacuum hose from the air intake tube before the TB to keep my base timing set...but I don't think this helps my power at high RPM. My car runs out of power around 5500rpm's and falls flat after the MPI/Cam/Header/Turbo install. Before, I had no problem going 6000+rpm's and it still seemed to be pulling. Where are you MPI guys getting your vacuum source from? I am using the stock Distro. My mechanical advance is working. On the Dyno graph it shows a steady power increase from 2600-3700 rpm's to 170HP then it falls slightly and then slowly climbs to 191Hp at 4800rpm's before falling off. At 5500+ it stumbles. I was boosting at 15psi and had a good curve going at first...I need some help to sort this out. I'll post the graph as soon as I can find a host. Link to comment Share on other sites More sharing options...
WTFISIT Posted June 12, 2004 Report Share Posted June 12, 2004 I cropped and scaled the image a bit to make it a better fit. http://chaostrophe.com/quest/hotrodtsi_dyno.png Link to comment Share on other sites More sharing options...
HotrodTSi Posted June 12, 2004 Author Report Share Posted June 12, 2004 Thanks bro Link to comment Share on other sites More sharing options...
Vanishing Point Posted June 13, 2004 Report Share Posted June 13, 2004 I have never tried it but IM sure a machinist could bore some vacum hole slightly above the throttle plate for you to attach a hose and get the proper vacum curve. While your at it have a few drilled at different hieghts and when you find the best one plug the other ones. Use the stock TB as a guide to get started. After the hole is drilled it can be counter sunk and a piece of tubing pressed in for vacum hose. Link to comment Share on other sites More sharing options...
Joel Posted June 14, 2004 Report Share Posted June 14, 2004 What kinda of ECU are we dealing with? If your using a distributor and not the stock ECU to control timing, you don't want the mechanical advance or the weights in the sitributor at all. Vacuum sources in the Magna are done with a drill, tap and some hose barbs. Joel Link to comment Share on other sites More sharing options...
Boosted_One Posted June 14, 2004 Report Share Posted June 14, 2004 A check valve should work, but your vacuum advance will only function as either a vaccum advance OR a retard unit. If you have a check valve inline to only allow boost thru as a retard device that should work with a check valve. What you need is a ported vacuum source for the vacuum advance. Take a look at the stock TB to get an idea of what that is. It is basically a source tapped an inch or so above the vacuum nipple with a small drilled chamber inside that only allows a vacuum source when you really step on it. Depending on which ECU you are using you need to determine what set up will work. Fill us in a little more Link to comment Share on other sites More sharing options...
HotrodTSi Posted June 14, 2004 Author Report Share Posted June 14, 2004 I am using a SDS EM-D fuel only ECU. Joel, are you saying that I should remove the weights and springs from the distro? Boosted_One, I am using a 65mmTB from a 4.6L Ford. Would I tap a port that is in front of the throttle plate at idle, but would be close enough at part/full throttle to pull a vacuum? What size drill bit do you recommend? Can you post any pics of a proper setup? Thanks for any help you can give. Terry Link to comment Share on other sites More sharing options...
eck_007 Posted June 14, 2004 Report Share Posted June 14, 2004 has anyone else had this prob with a stock cam? how did the dist work with the stock tb and intake, whats the diff in a vac port from stock intake to mpi? i just cant understand the diff in a vac port on the stock intake and the mpi, they both have vacume. if i sound dumb sorry im just trying to fig this out Link to comment Share on other sites More sharing options...
pinale69 Posted June 14, 2004 Report Share Posted June 14, 2004 the problem is that stock dizzy needs some sort of elecrtonic control for knock sensing, etc. this is exactly why I went with the sds_f Link to comment Share on other sites More sharing options...
artinist Posted June 14, 2004 Report Share Posted June 14, 2004 well, at least your fuel mixture is good. now find a way to advance your timing. you should set the base timing at the factory spec., no need to start out with less timing. Link to comment Share on other sites More sharing options...
HotrodTSi Posted June 14, 2004 Author Report Share Posted June 14, 2004 art...i started with 10*BTDC but i had very little bottom-end power. at 16*BTDC i am in good shape. But as you say, i am giving up too much elsewhere. i will adjust it a bit and see what works good...but would like some more info on what Joel said about the advance weights. ...still would like to see some tapped ports that work for the vac advance. Link to comment Share on other sites More sharing options...
WTFISIT Posted June 14, 2004 Report Share Posted June 14, 2004 I think that Joel is mistaken, or is thinking about the E & F SDS systems. I think that with the D, you need to leave the entire stock ignition in place. You'll want both the mechanical and vacuum advance. Link to comment Share on other sites More sharing options...
HotrodTSi Posted June 15, 2004 Author Report Share Posted June 15, 2004 ahhh..ok, that was something I hadn't heard before. I think I am going to try some advice from mikec and add heavier springs to the weights to slow down my mech advance. Link to comment Share on other sites More sharing options...
Vanishing Point Posted June 15, 2004 Report Share Posted June 15, 2004 Heavier springs will slow your advance and make it worse. That was the old school way to adjust the advance curve. The problem with that is it comes in to slow and doesnt retard with boost because its already retarded. Heres another dumb idea attach a 1/4 turn valve to the throttle and run manifold vacum to it. Adjust it to open with any throttle over idle. you will have the advance and the retard. the biggest problem is hooking it up to your throttle. Make sure its adjustable so you can tune it just right. Tony Link to comment Share on other sites More sharing options...
Shelby Posted June 15, 2004 Report Share Posted June 15, 2004 in a raceing situation the vacum advance is of no use at all,, it does how ever still help in timeing advance,, to use the retard funtion with boost, simpley T it into the waste gate hose, then all it see's is pressure , there is no vacum on the hose to the waste gate you also adjust the timeing curve with no vacum advance, and with no boost it's also important to know what the max advance numbers are Link to comment Share on other sites More sharing options...
Boosted_One Posted June 15, 2004 Report Share Posted June 15, 2004 I am using a SDS EM-D fuel only ECU. Joel, are you saying that I should remove the weights and springs from the distro? Boosted_One, I am using a 65mmTB from a 4.6L Ford. Would I tap a port that is in front of the throttle plate at idle, but would be close enough at part/full throttle to pull a vacuum? What size drill bit do you recommend? Can you post any pics of a proper setup? Thanks for any help you can give. Terry NO NO NO NO Don't remove the weights. You would remove those only if you had an electronic programable ignition. The SDS 4D is fuel only. You'd be at baseline timing always and the car would run like tail. Are you sure you oriented the check valve correctly? For boost only? You'll get enough advance from your weights and you can get a few more if you bump the baseline up to 12 or 14*. I don't believe the Ford TB has a ported source. Basically a ported source has the source signal offset a bit to the actual port that the line goes to. The only thing I would really use the vacuum advance for is to retard timing. You really won't need it to advance timing seeing once you hit boost advance is nil via the vacuum actuator. Link to comment Share on other sites More sharing options...
Boosted_One Posted June 15, 2004 Report Share Posted June 15, 2004 in a  raceing  situation the vacum advance is  of no  use at all,, it does how ever  still help in  timeing advance,,  to use the retard funtion  with  boost, simpley  T it into the  waste gate  hose, then all it see's is pressure , there is no vacum on the  hose  to the waste gate you also  adjust the  timeing curve  with no  vacum advance,  and  with no boost it's also important to know what the max advance  numbers are HEY! There ya go! Just like a boost only signal for an external wastegate. You could plumb a special fitting right off the compressor side turbo outlet. That'll work! Now that is great thinking Shelby! 8) Link to comment Share on other sites More sharing options...
Shelby Posted June 15, 2004 Report Share Posted June 15, 2004 if you have an over the valve cover pipe or any pipe port ahead of the intake throddle plate you have a boost only port , the to6 compressor houseing has a couple bolt hole's that go into the compresor houseing so a port could be utilize'd there or a port can be add'd to the ic pipeing Link to comment Share on other sites More sharing options...
HotrodTSi Posted June 15, 2004 Author Report Share Posted June 15, 2004 ok, I'm using Kellys MPI hardpipe so I have a port just before the TB. I use it for the boost controller for the Turbo, so I tee'ed off it to the distributor. I'm going to reset the timing and see how it does. ...about using two heavy springs instead of one heavy/one soft(stock), mikec looked at my graph and suggested that my timing may be too fast and wanted to see if this would widen my powerband. Link to comment Share on other sites More sharing options...
Vanishing Point Posted June 15, 2004 Report Share Posted June 15, 2004 My mastake I was under the Impression this was a street car that was off boost part of the time. In that case you want all your timing in by 3000rpm at least that was the old rule. If your tuning for max HP only, next time you do a dyno session have a hand full of springs ready bring the timing in as early as possible without spark knock. Better would be ported vacum and leave the spring and weight mess behind. Sounds like your plowing new ground. Good luck Tony Link to comment Share on other sites More sharing options...
88whitestarion Posted June 16, 2004 Report Share Posted June 16, 2004 One problem I noticed in your set-up is your spark plug gap. If you are going to run greater than 15psi of boost you definately need to reduce your plug gap. I am currently runing 23 psi with a t3/t4 and mine will "blow out" a plug gapped at .035" at around 14psi. I initially tried gapping my plugs at .035 and it would run fine until I hit about 15 or so psi and then I would get these huge backfires. I lowered the gap to .028 and the problem immediately went away. It doesn't miss a beat with the lower gap through red line. As far as the vaccuum advance goes, I initially had the same problem until I removed the distributor weights and welded the vacuum advance shut and ran the timing from the Haltech. I am not familar with SDS to know if that is an option for you. Another problem I experienced this spring when I went to put it on the dyno with my new T3/t4 is it ran like crap. It would run pretty good but would start to miss and backfire when I tried turning the boost up past about 17psi. I couldn't figure out what was going on and tried regapping the plugs and new plug wires. I finally put some dielectric grease on my injector clips and solved the problem. Apparently the clips were getting a bad connection even thou the injectors and wiring harness for the Haltech were less than a year old. I hope this helps. Good luck, Dave Link to comment Share on other sites More sharing options...
HotrodTSi Posted June 17, 2004 Author Report Share Posted June 17, 2004 thanks Dave...as soon as my hardpipes get back from the powder-coaters I will be trying some tips from everyone who responded. I'll try the gaps at a few different settings to see if it helps. Link to comment Share on other sites More sharing options...
artinist Posted June 17, 2004 Report Share Posted June 17, 2004 dave, you seem to need a better coil, not so small of a plug gap. the small gap will not create a very good combustion. Link to comment Share on other sites More sharing options...
88whitestarion Posted June 17, 2004 Report Share Posted June 17, 2004 Artinist, I am running a red bosch coil with an MSD 6A, I really doubt the quality of my coil is the issue. The same issue was encountered with my old ignition set-up which was a Jacobs Pro Street ignition. Also I am putting over 400 ft/lbs of torque and 350 hp to the wheels without missing a beat. I don't think I have a inadequate combustion problem. I don't know if you have ever tried putting high boost with a large turbo before, because if you have I can just about promise you that you will have problems with a .035" gap. Dave Link to comment Share on other sites More sharing options...
pinale69 Posted June 18, 2004 Report Share Posted June 18, 2004 I'm running a .35 gap without any problems at 22psi on an 18G, but then again, I also have coil pack ignition and that added voltage really does help. the 100octane fuel I run with the 36degrees total advance and 20degree retard at 22psi couldn't hurt either Link to comment Share on other sites More sharing options...
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