mr jdm Posted August 7, 2011 Author Share Posted August 7, 2011 that means 430hp could only be made if the engine could make 193.3hp with no boost. (193.3 x 2.224 = 430). I am sure my sr20det without a turbo wouldn't dyno more than 155-160whp. Hitting 193whp on a non bosted sr20, only happens if you are using vvl head. Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 8, 2011 Share Posted August 8, 2011 I am sure my sr20det without a turbo wouldn't dyno more than 155-160whp. Hitting 193whp on a non bosted sr20, only happens if you are using vvl head. I see you are not using a completely stock sr20det setup. Do you think this could account for more than 160hp off boost? I hope your engine could make 193hp off boost, if not, then I would guess the dyno results are off a little. A blast down the 1/4 mile would also help determine hp. Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 8, 2011 Share Posted August 8, 2011 there are lots of boost calculators of the web that do what I'm talking about. Again, just a simple formula. here is one. http://www.csgnetwork.com/blowerhpcalc.html Quote Link to comment Share on other sites More sharing options...
mr jdm Posted August 8, 2011 Author Share Posted August 8, 2011 Those calculators are completely worthless, one major factor they dont input is RPM. Since we are talking about only peak output, where its going to redline is going to make a major change. The car made 400whp at 6,600 rpm on 18 psi. We upped the redline to 7k with no other changes and gained 30whp. Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 8, 2011 Share Posted August 8, 2011 (edited) power in a normally aspirated engine would also go up with rpm, so I'm not understanding your point. a turbo doesn't effect where the max power is made. the cam does that. if you have a 200hp engine that makes max hp at 7000 rpms then add 14.7 psi of boost then it will make 400hp at 7000 rpms, (14.7 +14.7)/14.7 =2. That is what will happen if everything is perfect. It can only lose power from there. Edited August 8, 2011 by Pyro Quote Link to comment Share on other sites More sharing options...
Matt K Posted August 8, 2011 Share Posted August 8, 2011 I think you'll be wanting to go slightly larger on your injectors, if you want to boost to that hp level. When I went over 400 rwhp, 850cc's weren't safe (long term) to sustain the over 500rwhp goal I was shooting for. I wound up switching to 1000cc injectors. Otherwise your injector duty cycle is going to be very sketchy. I'd also switch to a Bosh 044 fuel pump (or larger)...using the factory fuel pump power wire as your switched power through a 30-amp relay wired directly to you battery with 10-gauge wire (along with a 10-gauge ground wire). You can use a standard headlight relay from an autoparts store for that. My single Walbro 255 lasted a bit longer via that method, but it wasn't the proper way. You can keep using the current Walbro with the addition of another pusher pump & fuel surge tank (1-liter or larger) with your stock sized lines, but the best way would be to run larger lines with a real pump. Good luck! Welcome to the 500-hp club! Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 8, 2011 Share Posted August 8, 2011 Y'all should read some of those threads about boost pressure versus air flow. The pressure measured (boost) is essentially back-pressure or resistance to flow. Flow allows power and pressure increases flow, but flow probably does not increase with pressure linearly, in most cases. Quote Link to comment Share on other sites More sharing options...
mr jdm Posted August 8, 2011 Author Share Posted August 8, 2011 power in a normally aspirated engine would also go up with rpm, so I'm not understanding your point. a turbo doesn't effect where the max power is made. the cam does that. if you have a 200hp engine that makes max hp at 7000 rpms then add 14.7 psi of boost then it will make 400hp at 7000 rpms, (14.7 +14.7)/14.7 =2. That is what will happen if everything is perfect. It can only lose power from there. It's a wack calculator. PSI itself has not much to do with power levels. All things a side, 14.7 psi on a gt25r compared to 14.7 psi on a gt35r, not the same power. Psi doesn't matter, flow does. I think you'll be wanting to go slightly larger on your injectors, if you want to boost to that hp level. When I went over 400 rwhp, 850cc's weren't safe (long term) to sustain the over 500rwhp goal I was shooting for. I wound up switching to 1000cc injectors. Otherwise your injector duty cycle is going to be very sketchy. I'd also switch to a Bosh 044 fuel pump (or larger)...using the factory fuel pump power wire as your switched power through a 30-amp relay wired directly to you battery with 10-gauge wire (along with a 10-gauge ground wire). You can use a standard headlight relay from an autoparts store for that. My single Walbro 255 lasted a bit longer via that method, but it wasn't the proper way. You can keep using the current Walbro with the addition of another pusher pump & fuel surge tank (1-liter or larger) with your stock sized lines, but the best way would be to run larger lines with a real pump. Good luck! Welcome to the 500-hp club! The entire car has been rewired, engine harness and body harness. In the back is a fuel cell, -8 feed and return lines, and an external walbro, which a second one will be added in time along with larger injectors. I think it might be possible to clear 500whp, if I just add 4-5psi and raise the redline to 7,800 rpm with 72lb ijectors running 50 psi base if you are ok accepting a 90-92% duty cycle. Anyways, right now I dont even have a running car. I will look into tomorrow and update the thread. Quote Link to comment Share on other sites More sharing options...
Matt K Posted August 8, 2011 Share Posted August 8, 2011 Most injectors are prone to failure if repeatedly tasked to perform above 85% duty cycle...which is why I bring that up...I personally wouldn't be too comfortable staking my engine's longevity on something so easy to replace, especially considering you can nearly get back 100% of your money selling off the "old" 72lb injectors...just something to consider. It sounds like you've got a handle on the rest of the fuel system though. Good luck! Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 8, 2011 Share Posted August 8, 2011 "It's a wack calculator. PSI itself has not much to do with power levels. All things a side, 14.7 psi on a gt25r compared to 14.7 psi on a gt35r, not the same power. Psi doesn't matter, flow does." You are absolutely correct, boost by itself has not much to do with power levels. There also needs to be a base hp level for the equation to work. Yes, 14.7 psi on a gt25 is not the same on a gt35, you got it, as these engine will also have very different normally aspirated power levels. Different normally aspirated levels is the root cause of different hp gains from boost That is the entire point. 7.5 psi on a 1000 hp engine will make 1500hp and 7.5 psi on a 100 hp engine will make 150 hp. Very different hp gains but the same percentage gain. Hey, I didn't invent the boost theory. It is simple, doubling atmospheric pressure doubles the hp. simple physics. I don't understand why you don't understand the simple formula or why you don't want to hear it. But that is what it is. Quote Link to comment Share on other sites More sharing options...
mr jdm Posted August 8, 2011 Author Share Posted August 8, 2011 Quote Link to comment Share on other sites More sharing options...
mr jdm Posted August 8, 2011 Author Share Posted August 8, 2011 Pyro, this will be my last point. An Sr20det, without boost, makes about 140hp at the crank. We will use that as your base example. 140 Crank hp with 14.7 psi on a gt25r = your calculator answer, now if you tell me 140 crank hp with 14.7 on a gt42r = that same calculator answer, well, Im going to laugh. Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 8, 2011 Share Posted August 8, 2011 all I can say is, some people you just can't reach. Quote Link to comment Share on other sites More sharing options...
itzgoten Posted August 8, 2011 Share Posted August 8, 2011 Great to see you found your problem. Sucks that it's the frggin chain. Did you break or bend any other components? Quote Link to comment Share on other sites More sharing options...
mr jdm Posted August 9, 2011 Author Share Posted August 9, 2011 I was busy parting out a miata today, all I did was do a compression test and when I got zero on two cylinders I knew it was the chain and just popped the valve cover. I will take the head off probably on wednesday some time and see what I got going on. I am really hoping there isn't major damage. The chain slipped off at only 2,500 rpm. Quote Link to comment Share on other sites More sharing options...
itzgoten Posted August 10, 2011 Share Posted August 10, 2011 Well I'm hoping it'll just be a few bent valves? Also praying that the pistons didn't get damaged.. On a different note.. I own a Miata too! I guess people who like certain cars will have similar taste. I've had a s13, Miata and the Z. Quote Link to comment Share on other sites More sharing options...
TheMission Posted August 10, 2011 Share Posted August 10, 2011 Oh, the venerable Miata. LoL. I love them too, but could never get over the feminine design that I saw... Killer little cars in Auto-X though. I went for the S2k when I went through my 2 seater convertible phase. Decent enough performance, but man did it look good. If I ever do a little car again I'll go back to original minis with the honda swap in them... they are insane! I ran a ol' school mini for a while, but budget killed me at the time. I think a lot of the SR20Z guys are similar in their car tastes though... younger guys who love the old styling, but like the modern ECU'd turbo'd cars and the endless fun they have in such a small package. Timing Chain busting without damage... we can hope for miracles... I've seen a ton of belts break in the VW world and it's rare to come out unscathed. Quote Link to comment Share on other sites More sharing options...
mr jdm Posted August 10, 2011 Author Share Posted August 10, 2011 Miatas are alright, but I wouldn't own one. I only own them to part them out. I will post my damage results tomorrow. Quote Link to comment Share on other sites More sharing options...
mr jdm Posted August 10, 2011 Author Share Posted August 10, 2011 itzgoten, you ever take your car to the drag strip? Quote Link to comment Share on other sites More sharing options...
mr jdm Posted August 10, 2011 Author Share Posted August 10, 2011 Got the head off just now. No damage to pistons or any of the valves. Hopefully I can have it together tonight with new chain, tensioner, and guides. Time to find another boost controller and hit the dyno again. Quote Link to comment Share on other sites More sharing options...
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