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Man, oh man, am I going to have a badass intake setup for you guys soon. I need to remember to check this thread.
https://scontent-sjc2-1.xx.fbcdn.net...57&oe=5AFF6240 https://scontent-sjc2-1.xx.fbcdn.net...aa&oe=5AB4F9B3 |
Originally Posted by Tuning4life
(Post 12110507)
Here is some more info on my situation.
I don't think its compressor surge but something to do with the wastegate. The problem arises going uphill under high load at low rpm. Low rpm is 2500-3200RPM and it feels and sounds like the wastegate is fluttering which ends up like a jerking motion of the car. it only does it when the wastegate tries to control the boost. in order to get it in 4th you must be going uphill to drive the turbo to boost at that low of an rpm. but when you live in the mountains you have lots and large uphill sections, which sometimes you leave the car in fifth gear and get this stupid issue. It happens when you floor the car at low rpms and keep it floored, the wastegate feels like it is opening and closing or fluctuating, it steadies out with rpms as the rpms climb and then goes away completely. The car also does it at partial throttle as well over certain parts of the rpm range/boost pressures. does not do it at full throttle mid to high rpms at all. Remedy? Any suggestions? should I add more preload to the wastegate spring? I am running the stock wastegate canister from BW, medium pressure spring. I am running the stock BW supplied boost controller with the powerFC running it. The boost source is from the turbo like BW sent it to me. I am running the car at 6,500-9000FT above sea level if that matters. When looking at my water injection, it kicks on at this low level and when it starts jerking it looks as though the turbo is boosting on and off as the light is coming on and off on my water injection, so it makes me think that the UIM is seeing on and off boost patterns. perhaps the turbo is surging? I tried different boost settings, different injector duty cycles, shut off my water injection, none of this changed anything. it doesn't seem ignition related, and my AFR's are good. its something with either controlling the turbo or the turbo itself IMO. but willing to listen what others think. I know this is late to the party.... but I would think that it might be that your tuning in cells that you have not been able to access with the old turbo set-up is the problem. I had to re-tune most of the cells to the lower left of the PFC pages for fuel and ignition when going to the EFR turbo because it spools so much earlier. And you really magnify that situation at altitude and going up long inclines.... possibly setting up a circular pattern of boost / AFR / ignition timing in adjacent cells. Barry |
Originally Posted by ArmenMAxx
(Post 12064674)
I too am having surge issues at partial throttle lower rpms.
I am considering buying the Turbosmart BOV replacement for the standard BW unit. Anyone have any experience with this in terms of solving the partial throttle surge? My fd has a large street ported motor atm and an Adaptronic Select ECU. So, if I get a twin scroll internally gated EFR 8374 with Turblown's shorty manifold and custom vmount how early would my car hit boost? My goal is 3k. is that achievable? |
how early would my car hit boost? My goal is 3k. is that achievable? OK, how much boost are you trying to have by 3,000rpm? |
Originally Posted by BLUE TII
(Post 12246474)
3,000rpm goal.
OK, how much boost are you trying to have by 3,000rpm? As much as European 100 octane fuel can provide safely. I'm guessing around 16-17 psi? If you consider the following how early would a 7670 and an 8374 hit full boost at 16 psi?
Just to see if the extra time to spool up is worth it. |
Both the EFR 7670 and 8374 will hit 16psi around 3,000-3,400rpm on a 2 rotor depending on mechanical set-up, boost control/tuning, elevation, weight of car, gear, etc.
The 7670 will have slightly faster response, but the 8374 is no slouch. Here is a boost by rpm chart of my 7670 on a dyno dynamics. Boost came on a tad faster on Dynojet (26psi peak boost 3,800rpm on Dynojet instead of 4,000rpm on DD) and the street from more load I guess. https://cimg7.ibsrv.net/gimg/www.rx7...42f3bf8e30.png |
So you made 360whp with the 7670 at 26 psi?
We don't get e85 over here so 100 octane pump has is what i'll have to go with. i'd love if the 8374 reached 16 psi by 3400. I hear the 7670 is kind of weaker in terms of top end compared to the 8374. How does it feel on the road? |
Yes, with the EFR 7670 I made 369hp on the Dyno Dynamics peaking at 26psi (fading to 21psi boost at peak hp). I parked the car and the next weekend i did 420rwhp on a Dynojet again peaking at 26psi and fading to 21psi at peak hp. https://cimg0.ibsrv.net/gimg/www.rx7...848341a824.jpg https://cimg3.ibsrv.net/gimg/www.rx7...909a1025c7.jpg |
I hear the 7670 is kind of weaker in terms of top end compared to the 8374. How does it feel on the road? On high boost where I maxed the compressor flow out the EFR 7670 "lacking in high rpm power" on the street since like a piston engine car torque drops so fast after 5,000rpm. The EFR 8374 would provide more top end power with plenty of response and low end power when downshifting is always an option. My EFR 7670 build was for "racing" in a parking lot in 2nd gear. Remember terms like "lacking in power" are relative as when I tried high boost 4th gear freeway roll on on my 225/50-16 Hankook RS3 street tires it blew the tires of ~4,500rpm. On 255 DOT-R tires warmed up it held traction well in 3rd and up and on 255/55-16 MT Street drag radials warmed up and 12psi pressure it held traction in 2nd gear and up with gentle shifts. I think EFR 8374 is the right turbo for 90% of 2 rotors. |
wow that's a bid difference. I still haven't understood which one I should go with lol
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The 8374 will give you a linear powerband that compliments your engines natural powerband at those boost levels. Your whp should be getting towards mid 400's
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Originally Posted by WANKfactor
(Post 12246758)
The 8374 will give you a linear powerband that compliments your engines natural powerband at those boost levels. Your whp should be getting towards mid 400's
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^ get the 7670 or a v8 then. Also it depends on your definition of usable - the 8374 will get you around town at 3000 pretty bloody smartly. But if you want the same power and torque at 3000 as at 5000 forget about it. But if you are driving it in anger you wont be at 3000 rpm very often.
I was torn between the two turbos too - i didnt really neeeed 450hp, and wanted plenty of torque down low, but the 8374 just fit the engines breathing characteristics better and i like the idea of the compressor and the exhaust flowing better and more efficiently. Some times i think id like to try the 7670. The 8374 is pretty good though. Sorry to be of no help lol. |
I know this is a super tough choice for a 2 rotor- EFR 7670 or EFR 8374.
Both turbos can make ~300ftlbs torque at 3,000rpm and 16psi boost on the 2 rotor so you have to decide if making a bit more peak power (8374) or having that 300ftlbs available some thousandths of a second sooner after pressing the gas (7670) is more of a priority. If making more than ~300ftlbs torque at 3,000rpm is the priority you might want to look at even smaller turbos like EFR 7163 or a bigger engine. |
Originally Posted by BLUE TII
(Post 12246756)
I think EFR 8374 is the right turbo for 90% of 2 rotors.
My (completely non-EFR, lol) PT6466 is very responsive, surprisingly so (although the system was set up to optimize response)...... I need to take some logs of the boost response :djcelebra |
Originally Posted by Andreas Avgeris
(Post 12246762)
mid 400whp at 16 psi or higher? I'm looking for usable power at 3000rpm :burn:
Generally if you have a medium to a large streetport the 8374 will fit the engine characteristics better. Stock/small streetport 7670 does really well 3-400rwhp. |
Originally Posted by Andreas Avgeris
(Post 12246762)
mid 400whp at 16 psi or higher? I'm looking for usable power at 3000rpm :burn:
Why are you in such a high gear? What are you doing? You do realize fuel economy is better at higher RPM, low load, and transmission lifespan is better there too. If you keep lugging a motor around, expect issues... |
Originally Posted by Turblown
(Post 12246843)
You can definitely make 400rwhp at 16psi on the 7670 kit.
Generally if you have a medium to a large streetport the 8374 will fit the engine characteristics better. Stock/small streetport 7670 does really well 3-400rwhp. http://www.youtube.com/watch?v=WPchlUuNx1M Think I'm leaning towards the 8374 now.. The thing is though, what other mods can you do besides those i've already mentioned to minimize lag on this turbo? Do you guys have a dyno of an 8374 streetported fd at 16psi? |
Originally Posted by SirLaughsALot
(Post 12246870)
Sounds like you're driving the car wrong.
Why are you in such a high gear? What are you doing? You do realize fuel economy is better at higher RPM, low load, and transmission lifespan is better there too. If you keep lugging a motor around, expect issues... |
A car with 500hp probably makes 350hp for more of its rev range than a 350hp engine,, just sayin....
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Originally Posted by WANKfactor
(Post 12246903)
A car with 500hp probably makes 350hp for more of its rev range than a 350hp engine,, just sayin....
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You're English is perfect dude. The 8374 is definitely not nothing,nothing,boom. Its linear and progressive, possibly moreso than other turbos the same size. There will be boost at 2000rpm.
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Then 8374 it is.. Should i hope for 400whp at 16psi?
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I think it is more about the transient response than the boost thresh-hold - ie, how long after you press your right foot until boost comes on.
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Originally Posted by Andreas Avgeris
(Post 12246906)
Then 8374 it is.. Should i hope for 400whp at 16psi?
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