Rx7 boost well 1st & 2nd not any other
01-30-17, 06:05 PM
#1
Rx7 boost well 1st & 2nd not any other
I am stumped. I seem to get great boost response In first and second gear. Third gear seems to be sluggish. My set up is professional rotary built ported engine . For ems microtech lt10 and greddy prove elctrical boost controller. Aspec 6262 bb turbo kit with dual 46 precision wastegates. RE Vic. When I get full boost 15 lbs in 1st & 2nd gear the tires let loose. Third gear it almost seems as though one of the wastegates stays open and the acceratiom is not really there. He'll it even sounds different. The wastegates also blow out to the atmosphere
01-31-17, 06:21 PM
#4
It has been tuned but the primary injectors are two big. They will be switched and the car will be retuned. I will try to do a video on Thursday for coming back from 24 Daytona race I put gas and when I tried to turn her on she would not crank. Push started and drove it home. The car Sat for 12 years so little things are popping up.
01-31-17, 07:08 PM
#6
Racecar - Formula 2000
It's been a long time since I paid any attention to the boost setup, but...
I seem to remember a thread from way back where 1st & 2nd boost was OK, but fell off in higher gears. IIRC, it was caused by not getting to the 2nd turbo in 1st & 2nd - not enough time to trigger it. so it seemed fine there.
In higher gears when the transition occurred, the 2nd turbo wastegate would not close properly causing a boost loss. So it sounds exactly like what you have. However, I don't remember the root cause.
Try looking under "T" for "Turbo troubleshooting" in this post : https://www.rx7club.com/3rd-generati...0/#post3396507
I seem to remember a thread from way back where 1st & 2nd boost was OK, but fell off in higher gears. IIRC, it was caused by not getting to the 2nd turbo in 1st & 2nd - not enough time to trigger it. so it seemed fine there.
In higher gears when the transition occurred, the 2nd turbo wastegate would not close properly causing a boost loss. So it sounds exactly like what you have. However, I don't remember the root cause.
Try looking under "T" for "Turbo troubleshooting" in this post : https://www.rx7club.com/3rd-generati...0/#post3396507
Trending Topics
01-31-17, 07:18 PM
#8
Racecar - Formula 2000
02-03-17, 07:19 PM
#11
Yes. That is a good idea but he is very tied up. He did mention the primary injectors are to big and we will be swapping them and returning. My Mechanic is not a real fan of the twin dual wastegates. He says more complicated more to go wrong. Either way maybe it is the injectors and eventually he will iron out the problem. I also take a great interest in how to trouble shoot my car. Knowledge is power. One of the reasons I joined this forum is to share my rotary passion with others but to also educate myself on my car
02-08-17, 08:01 PM
#15
Rotary Enthusiast
Heres the links:
https://youtu.be/OoLYfcVqm4o
https://youtu.be/sKRy_9RLU08
by the way, The first video feels like it should be playing during the credits of the next fast and furious with that music haha!
https://youtu.be/OoLYfcVqm4o
https://youtu.be/sKRy_9RLU08
by the way, The first video feels like it should be playing during the credits of the next fast and furious with that music haha!
02-23-17, 08:55 PM
#17
Talked to my Mechanic he cant figure it out why it is running this way. I loose some boost in those gears also. He is a great engine builder but deals with drag cars mostly. I don't believe he has a lot of experience with dual wastegate set ups. This would make sense since most straight line cars are in the boost the for using a single wastegate set up. At this point I would be happy with someone just pointing me in the right direction. Anyone know of a reputable shop that can be trusted with this job. I am in Orlando.
02-24-17, 09:23 PM
#20
Kilo does my work and he does not like this setup. He is great but has not been able to get it right. He rather me go single wastegate but I already have a lot invested in this setup and want fast turbo response. Not to say single wastegate is not an option but I rather find someone in Fl who may be experienced with a dual setup.
02-25-17, 10:07 AM
#23
RX-7 Bad Ass
iTrader: (55)
OK, you're going to need to do a bit of troubleshooting here.
First off, you need to narrow down where the problem is. If the wastegate is sticking open in 3rd or higher, you should be able to hear it. Are your wastegates venting to atmosphere? If so it gets REALLY loud when you're on the throttle since the wastegates are open and exhaust is going straight out with no muffling.
So, if you get on it in 3rd gear and the car is super loud and not going anywhere, the wastegate could be open.
I would also try and rule out the boost controller. Vacuum line from the bottom port of each wastegate, to a brass T, then to the nipple on the compressor housing. That will run the wastegates at spring pressure. If you have 7 pound springs, should be around 7 pounds of boost (for example).
How is the wastegate/boost controller plumbed in? External wastegates can be odd to plumb in, there are 2 nipples, one on the top of the diaphragm and one on the bottom. The top one can hold the wastegate closed, the top can push it open. That gives very precise boost control, but it has to be hooked up right. The Profec B manual shows how to hook it up and you can Google it, there's a lot of vacuum diagrams for this setup.
Big thing here is eliminate problems. Could even be a sticking blow off valve venting all the boost to atmosphere or a boost leak. Final possibility could be something with the tune or ECU.
Dale
First off, you need to narrow down where the problem is. If the wastegate is sticking open in 3rd or higher, you should be able to hear it. Are your wastegates venting to atmosphere? If so it gets REALLY loud when you're on the throttle since the wastegates are open and exhaust is going straight out with no muffling.
So, if you get on it in 3rd gear and the car is super loud and not going anywhere, the wastegate could be open.
I would also try and rule out the boost controller. Vacuum line from the bottom port of each wastegate, to a brass T, then to the nipple on the compressor housing. That will run the wastegates at spring pressure. If you have 7 pound springs, should be around 7 pounds of boost (for example).
How is the wastegate/boost controller plumbed in? External wastegates can be odd to plumb in, there are 2 nipples, one on the top of the diaphragm and one on the bottom. The top one can hold the wastegate closed, the top can push it open. That gives very precise boost control, but it has to be hooked up right. The Profec B manual shows how to hook it up and you can Google it, there's a lot of vacuum diagrams for this setup.
Big thing here is eliminate problems. Could even be a sticking blow off valve venting all the boost to atmosphere or a boost leak. Final possibility could be something with the tune or ECU.
Dale
02-25-17, 10:23 AM
#24
Ecu is microtech and the wastegates both are vented to the atmosphere. 1 st and second gear the car comes unglued and the boost comes on strong. You can hear both wastegates working together. 3rd gear the boost does not come on the same and the sound is different. You can hear that they are not working as one unit. I am even scared to really get on it in third gear and above.
02-25-17, 12:15 PM
#25
RX-7 Bad Ass
iTrader: (55)
Try some of my suggestions - bypass the boost controller and see what that does to start with.
Also, check the hoses for cracks or tears. Any T's in the line MUST be brass or metal, NO PLASTIC TEES.
Dale
Also, check the hoses for cracks or tears. Any T's in the line MUST be brass or metal, NO PLASTIC TEES.
Dale