Vonlam43 Posted August 18, 2012 Share Posted August 18, 2012 Ok for starters I have a 77 280z 2+2 with n47/n42 combo fresh motor with a stage 3 schneider cam. I have everything to put a turbo on and was wondering what the max amount of boost I would be able to run on the stock injectors with an intercooler. I have been searching for about 2 days now and to no avail havent found anything. Some help would be much appreciated or pointed in the right direction thank you. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 18, 2012 Share Posted August 18, 2012 I'm no expert but I don't think that you have a good blend of parts for a well-functioning turbo engine. The stock EFI won't handle a turbo very well, and the Stage 3 cam is an NA cam, for example. The stock injectors won't supply enough fuel unless you crank up the fuel pressure, which will make everything rich off-boost. It would probably never run right. This thread is worth reading - http://forums.hybridz.org/index.php/topic/50208-the-ultimate-l28et-guidewhat-you-need-for-350whp/ Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted August 19, 2012 Share Posted August 19, 2012 What do you mean everything to put a turbo on? Your biggest mechanical factor is the injectors. Like NewZed said you'd have to ramp up the pressure, and that will never make it run right. But you could maybe get away with 5-7psi with it like that. Don't know how long it would last though. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted August 19, 2012 Share Posted August 19, 2012 Go check out an injector sizing calculator and see how much power the ~180(?) cc injectors will support. Quote Link to comment Share on other sites More sharing options...
roger280zx Posted August 19, 2012 Share Posted August 19, 2012 That cam is nearly too much for stock injectors/ecu WITHOUT a turbo. Quote Link to comment Share on other sites More sharing options...
Vonlam43 Posted August 20, 2012 Author Share Posted August 20, 2012 I shouldn't say stage 3 its a cam i pulled out of my parts car and had it reground it has very minimal overlap. Thank you NewZed that was a great article that really shed some light on my subject right now it looks like the weakest link in my going in setup will be the injectors and fuel pump but it will give me some room to play with and grow. Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 22, 2012 Share Posted August 22, 2012 You are using stock dished pistons, right? First, I would install a stock P79 or P90 head on your current block. This will lower the compression to 7.4:1 cr and give engine a better turbo cam. At least put in a stock NA cam. You can turbo charge the stock 8.3:1 cr setup (N42/N47) but ignition timing will need to be lower. Then find a stock t3 turbo with wastgate, j-pipe, downpipe, exhaust manifold, and turbo oil pan. What you need for the fuel enrichment for a turbo is called a FMU, you can get one on ebay for $100.00. This little device installs in the return fuel line and will increase fuel pressure only during boost. I would get a 6 or 8:1 fmu, The engine will need around 60 psi of fuel pressure with 7 to 8 psi of boost when using stock NA injectors. 60 psi is about all a stock efi pump will make while providing enough flow. Then you need to lock the mechanical advance in the distributor and set the timing to 28-30 degrees if you use 7.4:1 cr and stock boost (7-8 psi), or 24 degrees if you use 8.3:1. The fmu with locked timing makes a decent and cheap low boost turbo setup. But plan in the future to add an aftermarket efi system with ignition timing control. You can use your current cam if you use a stage 5 T3 turbine, but the engine will not make boost until 3500 to 4000 rpms, and that is no fun in a street car. Change the cam and springs, or just install another head with a stock cam. Quote Link to comment Share on other sites More sharing options...
Vonlam43 Posted August 23, 2012 Author Share Posted August 23, 2012 You are using stock dished pistons, right? First, I would install a stock P79 or P90 head on your current block. This will lower the compression to 7.4:1 cr and give engine a better turbo cam. At least put in a stock NA cam. You can turbo charge the stock 8.3:1 cr setup (N42/N47) but ignition timing will need to be lower. Then find a stock t3 turbo with wastgate, j-pipe, downpipe, exhaust manifold, and turbo oil pan. What you need for the fuel enrichment for a turbo is called a FMU, you can get one on ebay for $100.00. This little device installs in the return fuel line and will increase fuel pressure only during boost. I would get a 6 or 8:1 fmu, The engine will need around 60 psi of fuel pressure with 7 to 8 psi of boost when using stock NA injectors. 60 psi is about all a stock efi pump will make while providing enough flow. Then you need to lock the mechanical advance in the distributor and set the timing to 28-30 degrees if you use 7.4:1 cr and stock boost (7-8 psi), or 24 degrees if you use 8.3:1. The fmu with locked timing makes a decent and cheap low boost turbo setup. But plan in the future to add an aftermarket efi system with ignition timing control. You can use your current cam if you use a stage 5 T3 turbine, but the engine will not make boost until 3500 to 4000 rpms, and that is no fun in a street car. Change the cam and springs, or just install another head with a stock cam. Thanks again for all your help I just got it installed yesterday and working out all the bugs today will give updates on how everything works as soon as its on the road. Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 23, 2012 Share Posted August 23, 2012 A stage 3 cam will not work well with a stock turbine. A lot of back pressure caused by a restrictive turbine along with a lot of valve overlap is a bad combo. Quote Link to comment Share on other sites More sharing options...
Vonlam43 Posted August 25, 2012 Author Share Posted August 25, 2012 (edited) A stage 3 cam will not work well with a stock turbine. A lot of back pressure caused by a restrictive turbine along with a lot of valve overlap is a bad combo. I'm sorry I have a fmic setup 2 1/2 inch pipe t3/t4 hybrid turbo and a stage 3 turbo cam with 2 3/4 inch exhaust I think I'm just limited by the stock efi and the cylinder head but any feedback you turbo guys can give me is great and will be taken into consideration. The cam is a regrind and I had it done as close to the stage 3 turbo grind as they could. Edited August 25, 2012 by Vonlam43 Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 25, 2012 Share Posted August 25, 2012 Are you using a stock T3 exhaust turbine with your T3/T4 turbo? If so, it will not work very well with a lot of valve over lap. It is very hard to change the lobe separation angle on a regrind cam. And this is what typically makes the most difference between a turbo cam and a non-turbo cam. You will be much better off using a stock NA cam if you are using a stock T3 turbine. And Yes, the stock intake is not really designed for high rpm performance. I would consider 6500 rpm the max for a turbo setup using the stock intake. It will rev more but not ideal. Quote Link to comment Share on other sites More sharing options...
Vonlam43 Posted August 26, 2012 Author Share Posted August 26, 2012 No its a stage 3 turbine and good to know about the intake eventually I will buy an l28et and do it the proper way but everything is in and running and pulling decent at 5 lbs guess its time to turn up the boost and see were my limitations are. Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 26, 2012 Share Posted August 26, 2012 At what rpms is it reaching full boost? What fuel pressure are you using? Did you get a FMU? How much ignition timing? Quote Link to comment Share on other sites More sharing options...
Vonlam43 Posted August 26, 2012 Author Share Posted August 26, 2012 (edited) 24 degrees locked timing with vacuum advance hooked up full boost at about 2500rpm stock fuel pressure with the afm adjusted. This might be a stupid question but what is an FMU? Forget to mention underboost at any rpm full throttle my afr's are high 10's and low 11's. Edited August 26, 2012 by Vonlam43 Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 27, 2012 Share Posted August 27, 2012 (edited) That makes no sense to me. A stage 3 turbine making full boost at 2500 and afr's in the 10's and 11's with NA injectors and with no extra fuel pressure. All I can say is, with these results, you should be good to go. A FMU is a fuel management unit. It is what people use to add boost to an engine that was originally a NA setup. It goes in the fuel return line and increase fuel pressure only during boost. But it seems you don't need one, with afr's in the 10's. Have fun. Edited August 27, 2012 by Pyro Quote Link to comment Share on other sites More sharing options...
Vonlam43 Posted August 27, 2012 Author Share Posted August 27, 2012 Well hopefully it will all work out then now I have to figure out why my car keeps eating alternators and batteries Quote Link to comment Share on other sites More sharing options...
FricFrac Posted September 3, 2012 Share Posted September 3, 2012 Mega Squirt it then you can run the proper injectors and tune it properly. You'll be able to squeeze the most HP out that way.... Quote Link to comment Share on other sites More sharing options...
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