Datsunscom Posted June 16, 2010 Report Share Posted June 16, 2010 Kind of like the turbo in the dyno chart? Seriously, the plain bearing T67 on my L series 3 liter spooled before 4K rpm. Even with the larger .82 exhaust housing the VG30 should spool by 3500 rpm or so (without know the exact specs of the exhaust wheel, I can't make a more educated "guess"). I do know that a shot of nitrous spooling a large turbo is very entertaining. Dang, torque doubles from 200ft-lbs to 400+ft-lbs in a 1000RPM spread? That's without nitrous right? (As I'd expect N2O to have an even more pronounced spike). That thin must be entertaining on an auto-x course. Quote Link to comment
Datsunscom Posted June 16, 2010 Report Share Posted June 16, 2010 The only reason you would need back pressure in an exhaust would be if you had a turbo that was to large for the amount of volume the engine can possibly produce.. Guys like me that like the idea of ridiculous HP potential will get a larger turbo and play the game of backpressure balance...or just spray nitrous at it! On another not the injectors are in, but I ran out of time to retune! Hopefully Ill have it done next week :) Why not get a properly sized turbo in the first place? The problem with nitrous is in that sense it's a band-aid isn't it? I'd think the most efficient way is to pick a horsepower level, get the smallest turbo that will make that HP level and then there's no balacing with backpressure and turbos. This gives you the broadest torque curve, better efficiency (less waste heat) and even better MPG. Seems to me having a bigger turbo than you can take advantage of is like having a 510CID V-8 but using a small carb and exhaust to restrict it to only 450hp. I too am aiming for the area of 475WHP but I don't plan on using a turbo that can flow 600HP, that would get me less power in the 2000-4000rpm range where street car engines live 99% of their life. In any case, glad to hear you got your new injectors in so next time you dyno you can fully tune it and make 'er rip! Quote Link to comment
cjr198car Posted June 16, 2010 Author Report Share Posted June 16, 2010 What is this graph demonstrating? Full boost seems to come in at @ 4000rpm if not later (that huge swooping effect is the turbo spooling, you can see the leveling of power just after 4000rpm). How is this different than my setup other than the amount of boost? Am I missing something? Edit: Im sure Im missing something. 510six please explain. Quote Link to comment
cjr198car Posted June 16, 2010 Author Report Share Posted June 16, 2010 Datsunscom, I appreciate your criticism, but I think I have a well matched turbo. Many other guys on the z31 performance forum have purchased the exact same turbo in the exact same specs. I think the turbo will match my engine perfectly with an exhaust and tune. If I want a faster spool I will address getting more air into the engine and out of the engine faster (headwork/custom intake manifold). Do you have a build thread for the monster you are creating :) Quote Link to comment
fo0manchu Posted June 16, 2010 Report Share Posted June 16, 2010 i like your setup and turbo choice. Going to make some great numbers!! However i think the logic about turbo spool and back pressure is flawed. The only thing i see that might help that big turbo "seem" to spool faster(by having back pressure) is by the heat created because of the back pressure. Hence increasing the velocity of the exhaust gasses to the turbo a little more. I think you answered your own question, when you said that back pressure puts pressure on the turbine. Try putting pressure up against a fan by holding it and see if it spins faster. Most likely not. Its the same idea that you don't want pressure coming back on the compressor side(compressor surge). It will end up destroying the turbo. Anywho, i'm sure everyone on here can do their own research about turbo spool time. Should do 2 dyno's with different size exhaust to see the difference. :D j/k, seriously though at 7-10 psi i dont think you will see much difference in spool time and HP levels due to exhaust size(unless its like 2", hah). Great project, can't wait to see more pictures. Quote Link to comment
Datsunscom Posted June 16, 2010 Report Share Posted June 16, 2010 Datsunscom, I appreciate your criticism, but I think I have a well matched turbo. Many other guys on the z31 performance forum have purchased the exact same turbo in the exact same specs. I think the turbo will match my engine perfectly with an exhaust and tune. If I want a faster spool I will address getting more air into the engine and out of the engine faster (headwork/custom intake manifold). Do you have a build thread for the monster you are creating :) Fair enough - all that matters is you're happy with it, I'm just offering other thoughts is all. I don't have a build thread per se but mine is a VG30DETT swap, so not quite apples to apples with the SOHC cars. Quote Link to comment
510six Posted June 16, 2010 Report Share Posted June 16, 2010 What is this graph demonstrating? Full boost seems to come in at @ 4000rpm if not later (that huge swooping effect is the turbo spooling, you can see the leveling of power just after 4000rpm). How is this different than my setup other than the amount of boost? Am I missing something? Edit: Im sure Im missing something. 510six please explain. My point is that the turbo on the dyno chart has a "P" trim exhaust wheel with an .82 T3 housing, if your exhaust wheel is smaller than a P trim the turbo should spool a little quicker and the compressor being smaller helps too. I think your setup is really cool and I understand using the N20 to spool the turbo (nitrous and turbos go together better than peanut butter and jelly). What I was guessing is that the turbo has "room to grow" if you decide to put really big injectors and make 450-500 rwh in the future as the other mods look quite capable of supporting the horsepower. The turbo on the dyno used no nitrous and the car isn't set up to go around cones , it is more in tune with putting the hurts on BB Chevys at the Drag Strip and thrashing Vipers in freeway roll ons. BTW I look forward to the VG30's first "kill" stories. Quote Link to comment
Datsunscom Posted June 16, 2010 Report Share Posted June 16, 2010 The turbo on the dyno used no nitrous and the car isn't set up to go around cones , it is more in tune with putting the hurts on BB Chevys at the Drag Strip and thrashing Vipers in freeway roll ons. BTW I look forward to the VG30's first "kill" stories. 420whp...I'm guessing low 11's at about 120-ish MPH with slicks? Quote Link to comment
510six Posted June 17, 2010 Report Share Posted June 17, 2010 420whp...I'm guessing low 11's at about 120-ish MPH with slicks? The clutch slipped at 18 psi and 440+ rwh ,the plan was to make 500 rwh. At 17 psi it was good enought to play with new 600cc sportbikes and beat a Viper in a roll on. Once the "built" motor goes back in the car the plan is for 500 rwh on boost and another 100rwh with a small shot of nitrous, the 1/4 mile time will be what traction (control) will permit. When I saw the VG30 build the big turbo and the nitrous I saw the potential for a 500+ hp 510. Quote Link to comment
cjr198car Posted June 17, 2010 Author Report Share Posted June 17, 2010 Update: The electromotive tec3 I have is running old software and in need of an update (having a few communication issues between the laptop and tec3). Instead of upgrading with the available free software Im sending in my tec3 brain box for a wintec4 update (its like turning my tec3 into a tec3R). Ill have easier menu navigation and improved oversight on the tuning process. The new setup also takes a new approach to monitoring engine functions, resulting in a more integrated on-fly tuning process...sweet! Cool screen shots! -Colton Quote Link to comment
Datsunscom Posted June 17, 2010 Report Share Posted June 17, 2010 Update: The electromotive tec3 I have is running old software and in need of an update (having a few communication issues between the laptop and tec3). Instead of upgrading with the available free software Im sending in my tec3 brain box for a wintec4 update (its like turning my tec3 into a tec3R). Ill have easier menu navigation and improved oversight on the tuning process. The new setup also takes a new approach to monitoring engine functions, resulting in a more integrated on-fly tuning process...sweet! -Colton Bitchin', keep the updates coming. Quote Link to comment
cjr198car Posted June 18, 2010 Author Report Share Posted June 18, 2010 Ecu is sent to Electromotive. Im also purchasing a GPO solenoid to control boost through the Tec! I should have dyno time by the 29th. -Colton Quote Link to comment
elmerfudpucker Posted June 18, 2010 Report Share Posted June 18, 2010 So let me get this.. your useing the NOS as an on-demand not as a prespooler right? I had a GT that the boys wired in,once armed, nos would kick in and spray till the turbo could take over. I loved the power off the line and the shots was shorter, I didnt have to refill the damned thing so often. Quote Link to comment
Datsunscom Posted June 18, 2010 Report Share Posted June 18, 2010 So let me get this.. your useing the NOS as an on-demand not as a prespooler right? I had a GT that the boys wired in,once armed, nos would kick in and spray till the turbo could take over. I loved the power off the line and the shots was shorter, I didnt have to refill the damned thing so often. How big was the turbo on that thing? Quote Link to comment
cjr198car Posted June 18, 2010 Author Report Share Posted June 18, 2010 The nitrous is on demand. I may switch the setup around, but Im not playing with it yet. Quote Link to comment
metalmonkey47 Posted June 19, 2010 Report Share Posted June 19, 2010 Wow, look at that spike in power when boost kicks in. That looks fun and scary and the same time. VTAC yo. lol Loving that car. Quote Link to comment
cjr198car Posted June 29, 2010 Author Report Share Posted June 29, 2010 waiting for ecu so i got the bug to clean up the wiper motor. Before: During: After: Not bad for $7 (paint and new hardware). -Colton Quote Link to comment
metalmonkey47 Posted June 29, 2010 Report Share Posted June 29, 2010 That makes me wanna go do mine. lol Quote Link to comment
cjr198car Posted July 28, 2010 Author Report Share Posted July 28, 2010 Car is running great. No hard dyno #'s, but im running 15psi. No traction in first, second, or third. Quote Link to comment
fo0manchu Posted July 28, 2010 Report Share Posted July 28, 2010 your car is awesome! Quote Link to comment
Datsunscom Posted July 28, 2010 Report Share Posted July 28, 2010 Car is running great. No hard dyno #'s, but im running 15psi. No traction in first, second, or third. Excellent to hear, time for some traction control :-) Quote Link to comment
jputz Posted November 7, 2010 Report Share Posted November 7, 2010 Sounds like some mini tubs and some meatier tires are in order. I think you just made my mind up, VG it is. Thank you for the inspiration!!! Beautiful Car Josh Quote Link to comment
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