drunkenmaster Posted July 20, 2003 Share Posted July 20, 2003 Is there anything inherently wrong with the L28ET turbo manifold or has anyone found significant gains by making up a custom tuned length manifold? I need to know whether to purchase a nissan manifold or make one. Thanks guys. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 20, 2003 Share Posted July 20, 2003 What are your power goals? Quote Link to comment Share on other sites More sharing options...
drunkenmaster Posted July 21, 2003 Author Share Posted July 21, 2003 around 250hp at the rear wheels Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted July 21, 2003 Share Posted July 21, 2003 Use anything you want. At those power levels, all of them work fine. Quote Link to comment Share on other sites More sharing options...
drunkenmaster Posted July 21, 2003 Author Share Posted July 21, 2003 at what power levels does the stock manifold become an issue and why? Thanks Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 21, 2003 Share Posted July 21, 2003 It probably becomes a bottleneck at 450rwhp or so. Its just a bit restrictive at that point. An equal length tuned header won't net you as high a percentage of performance gain as it would on an NA engine. I'd definately stick with the stock cast manifold in your situation. Quote Link to comment Share on other sites More sharing options...
drunkenmaster Posted July 21, 2003 Author Share Posted July 21, 2003 450rwhp = 330rwkw = some serious power! do people have L28's putting that kind of power down? The fastest car i know locally has around mid 200rwkw and is already netting a very low 12 second 1/4 which is more than I could hope for for a daily driver. Thanks guys Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 21, 2003 Share Posted July 21, 2003 Thinking about it its probably lower than 450rwhp than it becomes an issue, more like 400. SleeperZ was the 400ft-lbs guy, check out the details here: http://www.hybridz.org/phpBB2/viewtopic.php?t=23649 313rwhp, 417ft-lbs of torque. As for 400+rwhp setups, there are a few on this board, but they aren't too common. Quote Link to comment Share on other sites More sharing options...
drunkenmaster Posted July 21, 2003 Author Share Posted July 21, 2003 Thanks Dare I ask the fuel economy of some of you guys running turbo L28's Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted July 21, 2003 Share Posted July 21, 2003 It should be ok, providing you keep your foot out of it. Quote Link to comment Share on other sites More sharing options...
Clifton Posted July 21, 2003 Share Posted July 21, 2003 I made 360 rwhp @ 15 psi and 417rwhp @ 22 psi. My turbo is my HP limiting factor. There are other things that will limit your power before the ex manifold. Quote Link to comment Share on other sites More sharing options...
jeffp Posted July 21, 2003 Share Posted July 21, 2003 I was running a stock manifold that I did a little work on. I port matched the turbo inlet, opened up the exhaust ports somewhat. My last dyno pull got me 413 hp and 475 foot pounds of torque at the wheel. Really, the stock manifold will do just about what ever you want it to do within reason. I have found that if you take the time to port match and open up the inlet to the manifold the part works well. I was just not to sure about getting 600hp from the unit. The other consideration is the waste gate for the turbo, that seems to be a factor in the whole setup. I was running a stock exhaust turbine housing machined for a stage 5 exhaust turbine wheel and it did well. I was @ 20psi of boost by 3K rpm's not to bad. The waste gate in the stock housing was starting to give me a little trouble as I did have a little boost creep at the higher rpm levels, so keep that in mind. Here is the thing I liked about the stock manifold. Being a log type setup, the run to the turbo was short. This plays a significant role in the exhaust gases that are turning the turbine. Keeping the run short will keep the exhaust hot, and the Volume of the exhaust will be more just because there is not all of the long runner to fill before you get it to the turbo. When you start getting the longer run to the turbo, it takes more volume of exhaust to fill and pressurize the inlet of the turbo that will turn the turbine wheel. I am not so sure that there is enough volume in the L28 to properly fill and produce the required exhaust to effectively turn the turbine at the lower rpm levels to get a quick response turbo. Just my thinking here, but like some say, if it isnt broke dont fix it. When I was ready to take the turbo off for a bigger exhaust turbine housing, I decided to do a back pressure test of the system to get an idea of what would change in the system with the bigger A/R exhaust turbine housing. I was very plaesed to find that my back pressure was running 1:1 so at 23 psi of boost @ 7K rpm I was getting 23psi of back pressure @ the inlet of the turbo, this was vary good for any application. So my thinking now is that with the bigger turbo pushing 30-35psi of boost to get me to the 600Hp range, the new setup should be excellent with the .70 A/R exhaust turbine housing machined to 2 1/2", running the stage 5 exhaust turbine wheel. I should never hit the breaking point on the back pressure curve to make the added boost ineffective. The question remains, how fast will the boost come up and at what rpm. I am hoping and thinking that 3K will be right in the ball park for my new build. If I can be at 30psi of boost @ 3k rpm, I will be very happy, and 5k rpm look out, because my engine will be putting out some real power at that point. So that is what I have found with the stock exhaust manifold, my thoughts on the system and how I accomplished my results. hope that helps. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted July 21, 2003 Share Posted July 21, 2003 Thanks Dare I ask the fuel economy of some of you guys running turbo L28's Averaging 10mph over the 75mph limit in Colorado, I get 27 mpg. That Z31 ECU really knows how to close the loop for economy. I also have 205 width tires, lowered springs, and a front air dam. Quote Link to comment Share on other sites More sharing options...
drunkenmaster Posted July 21, 2003 Author Share Posted July 21, 2003 Thanks for the good info guys. Quote Link to comment Share on other sites More sharing options...
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