Why be afraid of big turbos?
Sep 1, 2014, 11:32 AM
#20
Sep 1, 2014, 03:20 PM
#22
well neither one of those setups has an optimized spool area. the benchmark for me for a 900whp setup would be 400tq at 4500 or better. this graph is a 9180 on 4b11 2.2liter. it had fueling issues when shut down. but power was climbing at 7700. i did some comparisons a few months back between the 9180 and 6466 and found an open scroll 6466 on 4g63 making 400tq at 4500. cant find it now. but i assure you anything a 4b11 can do a 4g63 can do better. basically not the best comparison for what he was trying to portray. even arashi's 6466 made 400tq at 4900 when it was a 2.0. so not sure why it would be making less with more CC.
Sep 2, 2014, 10:12 AM
#23
Dual MIVEC vs no MIVEC is significantly important. Also the EFR has a Gamma Ti wheel and shaft that weighs half as much as these. One thing no 4G63 will ever do is spool like a 4B11 for the equivalent size. The only big turbo car I have seen spool like a 4B11 is Jeff's and that is a bunch of sorcery (and methanol) anyway.
Sep 2, 2014, 02:26 PM
#24
Agree with Aaron on 4b11 spooling faster, I won't get into any more than that as its way off topic. Yes Chris' evo x 9180 is an awesome setup, still not tapped out and still on stock head and lots of other stock items holding spool and top end back.
Anyway, this is what I have seen on a lot of turbos, twinscroll t4's in particular. Bigger turbos with twinscrolls and a big enough A/R and they typically spool the same as a smaller t3 based turbo but have a lot more top end.
I did run into some surge issues on my setup with my t4 twinscroll 6266 last year though, the turbo could spool at like 4,000 rpms (30psi or so) but I think it was just too much for my 2.2L to ingest, but spool was awesome!
To me there is a reason our turbos come with twinscroll...it works and I am always surprised people tend to stay away from them on bigger turbos. The boost control is definitely and issue or pain but is doable.
Anyway, this is what I have seen on a lot of turbos, twinscroll t4's in particular. Bigger turbos with twinscrolls and a big enough A/R and they typically spool the same as a smaller t3 based turbo but have a lot more top end.
I did run into some surge issues on my setup with my t4 twinscroll 6266 last year though, the turbo could spool at like 4,000 rpms (30psi or so) but I think it was just too much for my 2.2L to ingest, but spool was awesome!
To me there is a reason our turbos come with twinscroll...it works and I am always surprised people tend to stay away from them on bigger turbos. The boost control is definitely and issue or pain but is doable.
Sep 3, 2014, 06:25 AM
#26
Dual MIVEC vs no MIVEC is significantly important. Also the EFR has a Gamma Ti wheel and shaft that weighs half as much as these. One thing no 4G63 will ever do is spool like a 4B11 for the equivalent size. The only big turbo car I have seen spool like a 4B11 is Jeff's and that is a bunch of sorcery (and methanol) anyway.
When i compare spool of setups i look for TQ per rpm. and how fast that TQ rises per rpm during spoolup. those are the two parameters that define what you foot feels when you hit the go pedal. I do not look at psi boost per rpm. if you do look at psi boost then sure the 4b11 spools faster. but that is because the head is so dang restricted. remember this definition of boost : its the air pressure measured at the intake manifold that IS NOT freely flowing through the motor. restricted air pumps produce higher psi at the manifold.
I dont spend a lot of time comparing big turbo setups because they are completely boring to drive on the street for me. when i hit my go pedal i want to be rewarded with gratifying TQ no matter what rpm I am at. big turbos just fail miserably at this. so i do a lot of comparisons of fun street turbos. I also look at both the 4b11 results and 4g63 results. i am the only guy on the planet that is running a 4b11 turbo on a 4g63. so it has me looking at results on both platforms. the FP green, red, black, and 71mm or all the exact same size wheels between the 4b11 and the 4g63. and if you compare say fp green spool as I define it there is no comparison how much slower the FP green TQs up on the 4b11. its a turd. you actually have to lower your TQ comparo numbers to be able to compare. the 4b11 makes about 40-50TQ less typically. and comparing HP results for say FP red. the highest i can find on 4b11 is about 565whp.. where the same turbo size on 4g63 has hit over 600whp many many times.
so I hope that clears it up. the 4g63 produces torque sooner in the RPM band than a comparable size 4b11. and it makes power WAAAY easier. the 4b11 was a de- evolution. a real disgrace as superior successor to the 4g63
Sep 3, 2014, 08:12 AM
#29
i will disagree with you on the 4b11 spooling faster. But let me quantify that statement a bit. while the 4b11 has dual mivec , a big plus, It has a HUGE minus in valve size and cam dynamics. the valve sizes are like 2-3mm smaller than 4g63. and the head is cam on bucket. cam on bucket cams look like triangles in profile. they are seriously deficient at holding valve open for any duration compared to the far superior 4g63 cam follower setup.
When i compare spool of setups i look for TQ per rpm. and how fast that TQ rises per rpm during spoolup. those are the two parameters that define what you foot feels when you hit the go pedal. I do not look at psi boost per rpm. if you do look at psi boost then sure the 4b11 spools faster. but that is because the head is so dang restricted. remember this definition of boost : its the air pressure measured at the intake manifold that IS NOT freely flowing through the motor. restricted air pumps produce higher psi at the manifold.
I dont spend a lot of time comparing big turbo setups because they are completely boring to drive on the street for me. when i hit my go pedal i want to be rewarded with gratifying TQ no matter what rpm I am at. big turbos just fail miserably at this. so i do a lot of comparisons of fun street turbos. I also look at both the 4b11 results and 4g63 results. i am the only guy on the planet that is running a 4b11 turbo on a 4g63. so it has me looking at results on both platforms. the FP green, red, black, and 71mm or all the exact same size wheels between the 4b11 and the 4g63. and if you compare say fp green spool as I define it there is no comparison how much slower the FP green TQs up on the 4b11. its a turd. you actually have to lower your TQ comparo numbers to be able to compare. the 4b11 makes about 40-50TQ less typically. and comparing HP results for say FP red. the highest i can find on 4b11 is about 565whp.. where the same turbo size on 4g63 has hit over 600whp many many times.
so I hope that clears it up. the 4g63 produces torque sooner in the RPM band than a comparable size 4b11. and it makes power WAAAY easier. the 4b11 was a de- evolution. a real disgrace as superior successor to the 4g63
When i compare spool of setups i look for TQ per rpm. and how fast that TQ rises per rpm during spoolup. those are the two parameters that define what you foot feels when you hit the go pedal. I do not look at psi boost per rpm. if you do look at psi boost then sure the 4b11 spools faster. but that is because the head is so dang restricted. remember this definition of boost : its the air pressure measured at the intake manifold that IS NOT freely flowing through the motor. restricted air pumps produce higher psi at the manifold.
I dont spend a lot of time comparing big turbo setups because they are completely boring to drive on the street for me. when i hit my go pedal i want to be rewarded with gratifying TQ no matter what rpm I am at. big turbos just fail miserably at this. so i do a lot of comparisons of fun street turbos. I also look at both the 4b11 results and 4g63 results. i am the only guy on the planet that is running a 4b11 turbo on a 4g63. so it has me looking at results on both platforms. the FP green, red, black, and 71mm or all the exact same size wheels between the 4b11 and the 4g63. and if you compare say fp green spool as I define it there is no comparison how much slower the FP green TQs up on the 4b11. its a turd. you actually have to lower your TQ comparo numbers to be able to compare. the 4b11 makes about 40-50TQ less typically. and comparing HP results for say FP red. the highest i can find on 4b11 is about 565whp.. where the same turbo size on 4g63 has hit over 600whp many many times.
so I hope that clears it up. the 4g63 produces torque sooner in the RPM band than a comparable size 4b11. and it makes power WAAAY easier. the 4b11 was a de- evolution. a real disgrace as superior successor to the 4g63
Sep 3, 2014, 08:23 AM
#30
Jerry,
The intake ports are bigger and have a better angle. This isnt the thread for 4B11 vs 4G63, I will make a separate one for that with pix and measurements. The exhaust ports suck out of the box but can be fixed pretty easy. Backpressure doesnt make the car spool better, that is why stock they have a 12cm housing. I agree with you in some regards about what is important as far as spool (tq rate vs rpm) but like I said that is a different subject. I have a dyno sheet of the 7285 on the Drag X in a 2.0L vs the 7285 on the SLR2.2 in Austin's car around here somewhere. The X gives up 150rpm despite being 10 percent smaller, which in the 4G63 is worth 400-500rpm.
Cam shape is irrelevant to duration-
The intake ports are bigger and have a better angle. This isnt the thread for 4B11 vs 4G63, I will make a separate one for that with pix and measurements. The exhaust ports suck out of the box but can be fixed pretty easy. Backpressure doesnt make the car spool better, that is why stock they have a 12cm housing. I agree with you in some regards about what is important as far as spool (tq rate vs rpm) but like I said that is a different subject. I have a dyno sheet of the 7285 on the Drag X in a 2.0L vs the 7285 on the SLR2.2 in Austin's car around here somewhere. The X gives up 150rpm despite being 10 percent smaller, which in the 4G63 is worth 400-500rpm.
Cam shape is irrelevant to duration-