Pyro Posted September 9, 2004 Share Posted September 9, 2004 Ever since I switch to a T4/T3 I wasn't getting full boost in 1st and 2nd. In 1st gear it would only boost to 5 or 6 psi before it hit red line then in 2nd it would start boosting at 3500 then slowly make 12 psi by 5500 rpms and not go any higher. However, in 3rd gear it would be at full boost by 3500. So I installed an ajustable pressure regulator so I can increase my boost with a twist of a dial. I have a Delta waste gate so boost pressure can be increased by applying a small positive pressure to the "atmostphere pressure side" of the wastegate. I tee'd in to the pressure line going to the wastegate to devert some pressurized air into the regulator. Then ran the regulated air into the other side of the wastgate. I dialed in the wastegate to 10 psi and set the pressure regualtor to 5 psi. Now it boosts to 15 psi in 3rd gear just like I expected. But the big difference is now 1st and 2nd go on full boost by 3500 also!!! Man, what a rush! Second gear now breaks the tires loose at 4000 rpms. I guess the positive pressure from the regulator is helping keep the wastegate closed in first and second gear. The wastegate must have been opening due to the large amount of air trying to exit the exhaust manifold in the lower gears. Now the t4/t3 seems as responsive as the stock T3 turbo! I was missing my T3 turbo but not anymore. I also going for the record of most HP with stock NA injectors and stock NA ECU. I running 100 psi of fuel pressure at 15 psi of boost and running 27 degrees of ignition timing without any problems. However, my fuel pump system consists of 3 pumps in series: a low pressure pump (Mallory 110) that feeds two high pressure pumps (MSD). This was the only way to deliver 100 psi with high volumes. Not the best way to do it but it will get me by until I install megasquirt. Finally, I can't believe no one knows the detailed cam specs for the MSA stage 1 turbo cam! Quote Link to comment Share on other sites More sharing options...
Afshin Posted September 9, 2004 Share Posted September 9, 2004 FYI: many injectors fail past 80-90 psi. Apart from overheating and failing, it has been verified that injectors many be unable to open when psi is in excess of 90. Point is you are playing with fire and are closer to blowing your engine from lean condition than you may realize. If you already know this and are willing to accept the significant odds that the injectors and hence engine may fail and don't mind an excuse to rebuild your engine, then keep on enjoying the rush (otherwise consider keeping max psi to 80 and turn down the boost a tad, and yes, I know how hard it is to do). Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted September 9, 2004 Share Posted September 9, 2004 HEED THE WARNING! PLEASE stop what you are doing and do EFI/Turbo the correct and safe way. Puzzles me why you would install 3 pumps and run 100psi instead of a set of used SVO 36# injs and a single Walbro pump. I know you are trying to prove a point, but to what end? To prove you can do what no one in their right mind would or should do? Quote Link to comment Share on other sites More sharing options...
Pyro Posted September 10, 2004 Author Share Posted September 10, 2004 I agree with what you are saying. I need to upgrade to an aftermarket efi to do it right. But that takes a lot of time, work, and money That is why it is easier to throw on another pump to get the pressure in need for the fmu. 100 psi isn't that much. A friend of mine uses 120 psi on his twin turbo Viper and the car is a daily driven monster. However, my turbo is in a 76Z with the stock ecu (non-turbo) so a FMU is required. Bigger injectors will make the car run super rich off boost, so I'm just trying to see how much I can get away with at the monent until I find the time to do it right. The car pulls strong to 6K and doesn't detonate or surge or kick. It pulls hard and smooth all the way to redline. The plugs look good and all systems seem to be doing great. So, I'm not to concerned with engine damage I do appreicate your concern but this is one of many car projects that I have going on and I could blow up the engine without any real hardship on my part. I have other cars to drive to work and this is kind of a toy right now. I thought it was just interesting how applying a little positive pressure to the atmostphere side of the wastegate could make huge gains in 1st and 2nd gear boost response. Could be usefull to install a weaker spring in your wastegate and use a regualtor to bring the boost back up and gain turbo responce at the same time. Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted September 10, 2004 Share Posted September 10, 2004 Sounds interesting (the fuel pressure). You should really go and dyno it while it's still kicking. Brian 81zxturbo 95slobaru Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted September 10, 2004 Share Posted September 10, 2004 the part that puzzles me is you say you have a t4/t3? so you have larger T4 exhaust side of the turbo and stock T3 compressor side of the turbo. Wouldnt this just create more lag and not really help out in more boost or HP in any way.. Just confused on that part.. Also Scottie is correct about the Fuel pressure.. That is playing with fire.. although.. it is your Z and toy.. Good luck with it.. Quote Link to comment Share on other sites More sharing options...
Pyro Posted September 10, 2004 Author Share Posted September 10, 2004 Sorry for any miss-understandings. I have a T40b with a H3 wheel on the intake compressor side and a T3, 0.63 a/r with a stage 3 wheel on the exhaust turbine side. Quote Link to comment Share on other sites More sharing options...
Afshin Posted September 10, 2004 Share Posted September 10, 2004 100 psi isn't that much. A friend of mine uses 120 psi on his twin turbo Viper and the car is a daily driven monster What determines if a certain pressure is high or not is the probability of mechanical failure associated with it, not the amount of pressure used by a friend with a great car. The point is not that an injector can never handle 100 or more psi as a definite rule...., but that the incidence of failure becomes significantly high. You certainly seem creative and as you said the car is running nicely. My point is that you are running a very real risk of injector failure (I know it's working right now) under full sustained boost, which will only take a fraction of a second to blow the engine. People with modified vipers, supras, skylines...blow engines ALL the time, even though the car could have been running great for the last year before the event. Trust me, when you push the limit of fuel delivery on high boost applications, failure is very common, people just don't talk or post about it as often as they do the dyno sheet.... As mentioned by Scottie larger injectors would be a much better choice. And no, you do not need a stand alone injection, all you need to do is adjust the spring tension on the AFM to compensate for the larger injectors, real easy to do, do a search and you will find info related to it. Jersey is one member who has used it quite successfully. Anyways, I'm just sharing my opinion and was concerned because I did not know if you relied on the car or if it an expendable toy as you mentioned. Quote Link to comment Share on other sites More sharing options...
Warren Posted September 10, 2004 Share Posted September 10, 2004 Hey, he does go by the name "PYRO", right??? Couldn't resist. Warren Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 10, 2004 Share Posted September 10, 2004 Hey' date=' he does go by the name "PYRO", right??? Couldn't resist. Warren[/quote'] ROFL I thought that same thing last night after I read this thread Okay I've asked this before as I'm also running an FMU... what is considered the absolute safe limit of fuel pressure without taking some huge risk? Who has actually failed injectors on a Z by running fuel pressures of 100 psi or higher? I know... I just KNOW this is gonna make me sound not so smart, but I know that BEGI, for instance, totally discredit the claim that injectors will jam or fail at pressures in that area, and advocate running such high pressures on turbocharged N/A applications using their FMU. Yeah I know taking the word from the guys trying to sell you the thing is not always the best choice, but I mean, this IS Corky Bells company, this is THE turbo guy that so many here say is the turbo genius, so I figure he can't be completely talking out of the wrong hole. Here are some quotes from the Bell Engineering FMU instructions: "Caution: There is a vague limit that exists with regard to maximum possible fuel pressure. The industry Barbara S (I have NO idea what this is referring to!!) of injectors jamming at 50psi and the flow not increasign with pressure is not correct. It is possible for a very large injector (90 + lbs/hr) to jam at 100+psi of fuel pressure. At anything less than that, jamming is not going to happen" "In general, do not try to exceed 100-110psi fuel pressure" "aftermarket turbocharged cars will need a minimum of 90-100psi for 7 to 8 psi of boost" Are they selling wholesale destruction of fuel injectors and engines here or what? I do agree on one thing... while I would be brave enough to run something like this on the street, where there will only be brief spurts of such high pressures (anyways I'm only running about 65psi right now), I would never risk running something like 100psi in a sustained racing type situation. And anyways I'm at least running stock turbo injectors... Pyro you're nuts running this stuff on N/A injectors. Quote Link to comment Share on other sites More sharing options...
Sparky Posted September 10, 2004 Share Posted September 10, 2004 Pyro, I expect to see you and your car the san antonio Z-club meeting this tuesday at chesters hamburgers on the 410 access road right after broadway (if heading north) meeting starts at 7:30....be there or be square. that is all. Quote Link to comment Share on other sites More sharing options...
Pyro Posted September 10, 2004 Author Share Posted September 10, 2004 Well, my G-tech meter just measured 271 hp with a car weight of 2800. I'm 200lbs, I have a full interior with AC, 2 amps, 2 subs, 2 woofers, 2 tweeters, custom speaker box, sound proofed and fiberglass floor boards, R200 diff, and a spare tire. I'm sure the turbo and IC add weight but I did remove the bumpers and bumper mounts. And all those fuel pumps and FMU add up to! LOL. So, most likely a little heavier than 2800 pounds. At 85 psi (100 psi fuel - 15 psi boost) a 17 lb injector will flow like a 28.6 lb injector. From RC Engineering web site: New flow rate= Square root of (new pressure/old pressure) then multiplied by old flow rate. In this case: new pressure =85 psi, old pressure = 30 psi, old rate= 17 lbs ((85/30) **1/2) x 17 = 28.6 lb to convert lbs to cc: 28.6 x 11 = 315 cc 315 cc injectors should be good for 315 hp in a 6 cylinder. 315 x 0.85 (15% drivetrain losses) = 267 hp at the wheels. This works as long as the injectors I have flow at 17lbs at 30 psi. Sparky, Unfortunately, I'm a little to busy for car clubs. Maybe one of these days I can make it out there. But thanks for the heads up. Quote Link to comment Share on other sites More sharing options...
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