Turbo converter..anyone pick up mph going to a tighter converter?
04-01-2012, 11:42 PM
#21
In my rx7 a few years ago we went from my old nitrous coan 8" 4000 converter to a PTC 3200ish spec'd for my turbo setup. Before it went 145, after on the same boost went 142 as my shift extensions dropped A LOT more with the tighter converter. I was dropping around 1400-1500rpm with the ptc, but only 300rpm with the coan. The coan couldn't take anymore power though, once we turned the car up the ptc worked perfect. So with the tighter converter we lost 3mph at the same power level.
04-02-2012, 11:38 AM
#22
Thanks for all the info, I'll probably lose mph knowing how stuff works. I just drove it for the first time and it is alot more entertaining, coupling alot early now, no more snowmobile cvt sound.
EDIT: Took it out again and logged it with my gps (10hz logging), it shows 2% slip at 6300rpm in 1st gear (81mph), that is way way way tighter than before. As expected, hitting it from 2000rpm cruise, the turbo spools up about half a second slower, but it feels quicker in general, probably isnt, but feels like it is. PTC got this converter exactly like I asked, cant believe a converter this good can be so cheap. I can still footbrake it to 3000 and build a few pounds of boost, difference is the rpm doesnt keep slowly climbing like the previous converter.
Other weird thing is I have been driving around on the same boost setting, wastegate springs for a while. It would always spike to 8# then fall instantly to 7.5#. Now it goes to 10# and stays there, maybe the tighter converter is loading the engine more, not sure.
Heres a pic rotary1307cc, thanks
EDIT: Took it out again and logged it with my gps (10hz logging), it shows 2% slip at 6300rpm in 1st gear (81mph), that is way way way tighter than before. As expected, hitting it from 2000rpm cruise, the turbo spools up about half a second slower, but it feels quicker in general, probably isnt, but feels like it is. PTC got this converter exactly like I asked, cant believe a converter this good can be so cheap. I can still footbrake it to 3000 and build a few pounds of boost, difference is the rpm doesnt keep slowly climbing like the previous converter.
Other weird thing is I have been driving around on the same boost setting, wastegate springs for a while. It would always spike to 8# then fall instantly to 7.5#. Now it goes to 10# and stays there, maybe the tighter converter is loading the engine more, not sure.
Heres a pic rotary1307cc, thanks
Last edited by Hank Peabody; 04-02-2012 at 12:17 PM.
04-07-2012, 01:11 PM
#24
Figured out my problem, #1 cylinder injector was NEVER connected, the splice had come apart when putting the car together originally. I was wondering where my missing 5mph was, it wasnt the converter! Car feels like 10psi was added with all eight cylinders firing for the first time.
04-07-2012, 02:53 PM
#25
Figured out my problem, #1 cylinder injector was NEVER connected, the splice had come apart when putting the car together originally. I was wondering where my missing 5mph was, it wasnt the converter! Car feels like 10psi was added with all eight cylinders firing for the first time.
please keep us updated on what it does at the track.
btw, love the car. I love the seeing the early rx7s racing, especially the big tire ones
04-07-2012, 08:04 PM
#26
Thanks! Yeah it ran good on 7 cylinders, I always though the idle was a little rougher than it should be, but it ran pretty decent, like it had a slightly lumpier cam or something. Amazing how much power getting that cylinder working added though! Hahaha
04-07-2012, 08:44 PM
#28
Typical stuff I do to myself, I should have known! Hopefully that piston is ok, with zero fuel and just compressed air, the spark shouldnt have been igniting anything. I really dont know how to explain the plug being black though. It wasnt oily or wet or crusty, just black.
The weird thing about the temp gun, the only reason I had one was I was debugging a carbed 302 trying to figure out if all cylinders were firing a few years ago, not sure why I never got it out on this car, it was just running so good I never though a whole cylinder was missing!
04-07-2012, 09:03 PM
#29
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It was down on mph at the track, thought it was the converter, that wasnt it. #1 plug was dark, all others were perfect, mistakenly drove home with #1 plug wire off and noticed this morning, it drove the same as always with the wire off. Compression was good and I was getting spark, even swapped coils and wires, still busted, knew it had to be fuel at that point. Matt(denmah) mentioned a temp gun on the manifold tubes, Im gonna start using that more. The car was down on power but if you didnt know it you wouldnt think it was missing a cylinder just driving around.
Typical stuff I do to myself, I should have known! Hopefully that piston is ok, with zero fuel and just compressed air, the spark shouldnt have been igniting anything. I really dont know how to explain the plug being black though. It wasnt oily or wet or crusty, just black.
The weird thing about the temp gun, the only reason I had one was I was debugging a carbed 302 trying to figure out if all cylinders were firing a few years ago, not sure why I never got it out on this car, it was just running so good I never though a whole cylinder was missing!
Typical stuff I do to myself, I should have known! Hopefully that piston is ok, with zero fuel and just compressed air, the spark shouldnt have been igniting anything. I really dont know how to explain the plug being black though. It wasnt oily or wet or crusty, just black.
The weird thing about the temp gun, the only reason I had one was I was debugging a carbed 302 trying to figure out if all cylinders were firing a few years ago, not sure why I never got it out on this car, it was just running so good I never though a whole cylinder was missing!
04-07-2012, 09:10 PM
#30
First place to start when you feel you're down on power 
http://www.amazon.com/Kintrex-IRT042...3850931&sr=1-1
I wish I would have taken 10 minutes to use that originally!!
http://www.amazon.com/Kintrex-IRT042...3850931&sr=1-1
I wish I would have taken 10 minutes to use that originally!!
06-01-2012, 09:49 PM
#33
EDIT: Took it out again and logged it with my gps (10hz logging), it shows 2% slip at 6300rpm in 1st gear (81mph), that is way way way tighter than before. As expected, hitting it from 2000rpm cruise, the turbo spools up about half a second slower, but it feels quicker in general, probably isnt, but feels like it is. PTC got this converter exactly like I asked, cant believe a converter this good can be so cheap. I can still footbrake it to 3000 and build a few pounds of boost, difference is the rpm doesnt keep slowly climbing like the previous converter.
Im pretty sure this weekend I will have the same issue. on 5# its only dropping 700rpms so Im sure when i turn it up to 9# it wont hardly drop.
also, Im only getting to about 5900 on the stock cam before it feels like its completely stopped accelerating . how high were you able to rev on the stock cam?
thanks man
06-04-2012, 04:35 PM
#34
My stock cam acted the same around 6000rpm on my LQ4 in my Monza/Sunbird, power really dropped off there, I was using a single 75mm s400.
PTC converters are pretty cheap for what they are. A turbo or nitrous converter rated by the guy I talked to at about 1000 engine hp is only $425-450.
I have to say after I sent mine back to get tightened, the one I had originally that I was concerned with being too sloppy really was perfect as it was. I didn't like the snowmobile cvt sound it made, but it felt a lot faster, boost was instant since it flashed so high under full throttle but was somehow super tight cruising. I also was missing a lot of power/performance, thought it must be the converter too sloppy, wound up being one of my injectors never hooked up, running on 7 cylinders for months and months. Im happy with the tighter one I got but the original looser one was definitely better for a drag strip setup. Now I have a T10 in the car after the shifter cable broke through the sheath and ran the trans between gears I guess
EDIT: DIdnt answer, not sure if they will rework your converter. Their converters are so good I'd probably just put out the $450 and get their whole converter.
PTC converters are pretty cheap for what they are. A turbo or nitrous converter rated by the guy I talked to at about 1000 engine hp is only $425-450.
I have to say after I sent mine back to get tightened, the one I had originally that I was concerned with being too sloppy really was perfect as it was. I didn't like the snowmobile cvt sound it made, but it felt a lot faster, boost was instant since it flashed so high under full throttle but was somehow super tight cruising. I also was missing a lot of power/performance, thought it must be the converter too sloppy, wound up being one of my injectors never hooked up, running on 7 cylinders for months and months. Im happy with the tighter one I got but the original looser one was definitely better for a drag strip setup. Now I have a T10 in the car after the shifter cable broke through the sheath and ran the trans between gears I guess
EDIT: DIdnt answer, not sure if they will rework your converter. Their converters are so good I'd probably just put out the $450 and get their whole converter.
06-04-2012, 07:01 PM
#35
My stock cam acted the same around 6000rpm on my LQ4 in my Monza/Sunbird, power really dropped off there, I was using a single 75mm s400.
PTC converters are pretty cheap for what they are. A turbo or nitrous converter rated by the guy I talked to at about 1000 engine hp is only $425-450.
I have to say after I sent mine back to get tightened, the one I had originally that I was concerned with being too sloppy really was perfect as it was. I didn't like the snowmobile cvt sound it made, but it felt a lot faster, boost was instant since it flashed so high under full throttle but was somehow super tight cruising. I also was missing a lot of power/performance, thought it must be the converter too sloppy, wound up being one of my injectors never hooked up, running on 7 cylinders for months and months. Im happy with the tighter one I got but the original looser one was definitely better for a drag strip setup. Now I have a T10 in the car after the shifter cable broke through the sheath and ran the trans between gears I guess
EDIT: DIdnt answer, not sure if they will rework your converter. Their converters are so good I'd probably just put out the $450 and get their whole converter.
PTC converters are pretty cheap for what they are. A turbo or nitrous converter rated by the guy I talked to at about 1000 engine hp is only $425-450.
I have to say after I sent mine back to get tightened, the one I had originally that I was concerned with being too sloppy really was perfect as it was. I didn't like the snowmobile cvt sound it made, but it felt a lot faster, boost was instant since it flashed so high under full throttle but was somehow super tight cruising. I also was missing a lot of power/performance, thought it must be the converter too sloppy, wound up being one of my injectors never hooked up, running on 7 cylinders for months and months. Im happy with the tighter one I got but the original looser one was definitely better for a drag strip setup. Now I have a T10 in the car after the shifter cable broke through the sheath and ran the trans between gears I guess
EDIT: DIdnt answer, not sure if they will rework your converter. Their converters are so good I'd probably just put out the $450 and get their whole converter.
I had briefly looked at converters and they were all in the $1000+ range so it is great to know I can get a good converter for under 5 bills.
sorry about the loss . t10 thats a manual trans right? how does it feel vs the auto?
06-04-2012, 11:55 PM
#38
yeah I have a 10'' PTC for my supercharged car, we started at 3200, were bumping it to 3400-3600 here soon, and it was more since it was for an FI car. just mention that, and what HP you will be running, or just have them cut back into it later on. they are great people to work with. as mentioned before. hard to believe a converter so good comes as such a great value. I drove to pick mine up, and it was worth it.
