First boosted autox - many growing pains
#1
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First boosted autox - many growing pains
After autocrossing this red race rat for 2 years on big grip and light weight alone, yesterday was the first time I brought it to the cone zone with a turbo on it. Setup as of now is a Greddy kit, adjusted to hit 4.5 psi (it was doing ~2.5 psi when I put it on) with a DIY intercooler - 12x18x3 core the same one Brain is using. BOV has not gone on yet. No MBC. Timing at 5* to be safe until I megasquirt.
Power up top in the rpm range was decent, but anywhere under 4k rpms it sputtered and trudged along and I had to sit and wait for it to hit 4k to begin to pull. I assume this is the problem that many fix with the o2 clamp? I'm thinking that the combination of the stock ecu leaning it out under 4k and the timing being down at the south pole at 5* that those were the cause of the complete lack of bottom end. Thoughts?
Also, in third gear the boost will pick up to a solid 4.5 and then just before redline it drops down to 3.5ish. But in second gear, it spools up to 4.5 around 4k and then by 5k it immediately begins to drop again, and gets all the way down to 2.5 psi by redline. Since I spend most of an autox in 2nd gear this is the most important area to be in boost... Is there a reason it drops off like that? Shoddy wastegate? What can I do to get it to hold boost to redline? I've heard a mbc helps with spool, but would it help with this issue? Should I be looking at a different wastegate - I've heard mention of the 300zx wastegate working on the TD04H is this true/a good idea for me?
Current plans are to add megasquirt with 400-something cc injectors and tune at 8 psi. Timing and fuel will be adjustable then. Also, will get my greddy knock-off bov adapter welded on and install that (recirculating) and will remove MAF. I think that should result in the car pulling much harder in the low end coming out of corners, and I'm hoping for it to hold boost through the powerband instead of tapering off.
Any thoughts?
-Ryan
Power up top in the rpm range was decent, but anywhere under 4k rpms it sputtered and trudged along and I had to sit and wait for it to hit 4k to begin to pull. I assume this is the problem that many fix with the o2 clamp? I'm thinking that the combination of the stock ecu leaning it out under 4k and the timing being down at the south pole at 5* that those were the cause of the complete lack of bottom end. Thoughts?
Also, in third gear the boost will pick up to a solid 4.5 and then just before redline it drops down to 3.5ish. But in second gear, it spools up to 4.5 around 4k and then by 5k it immediately begins to drop again, and gets all the way down to 2.5 psi by redline. Since I spend most of an autox in 2nd gear this is the most important area to be in boost... Is there a reason it drops off like that? Shoddy wastegate? What can I do to get it to hold boost to redline? I've heard a mbc helps with spool, but would it help with this issue? Should I be looking at a different wastegate - I've heard mention of the 300zx wastegate working on the TD04H is this true/a good idea for me?
Current plans are to add megasquirt with 400-something cc injectors and tune at 8 psi. Timing and fuel will be adjustable then. Also, will get my greddy knock-off bov adapter welded on and install that (recirculating) and will remove MAF. I think that should result in the car pulling much harder in the low end coming out of corners, and I'm hoping for it to hold boost through the powerband instead of tapering off.
Any thoughts?
-Ryan
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Two reasons I have not bumped it up to 6 psi yet:
Still using the Vortech FMU - so adding another pound and a half of boost would be upping the fuel pressure 18 psi, and it's already maxing the stock fuel pump.
Also, my wastegate must be weird because I adjusted it down almost to the max you can adjust it, AND put a 1/8" washer between the wastegate bracket and the turbine housing to pull it even farther back and now it's just barely hitting 4.5 psi. I literally don't think I can get it up to 6 psi with this wastegate without a MBC.
Still using the Vortech FMU - so adding another pound and a half of boost would be upping the fuel pressure 18 psi, and it's already maxing the stock fuel pump.
Also, my wastegate must be weird because I adjusted it down almost to the max you can adjust it, AND put a 1/8" washer between the wastegate bracket and the turbine housing to pull it even farther back and now it's just barely hitting 4.5 psi. I literally don't think I can get it up to 6 psi with this wastegate without a MBC.
#5
Two reasons I have not bumped it up to 6 psi yet:
Still using the Vortech FMU - so adding another pound and a half of boost would be upping the fuel pressure 18 psi, and it's already maxing the stock fuel pump.
Also, my wastegate must be weird because I adjusted it down almost to the max you can adjust it, AND put a 1/8" washer between the wastegate bracket and the turbine housing to pull it even farther back and now it's just barely hitting 4.5 psi. I literally don't think I can get it up to 6 psi with this wastegate without a MBC.
Still using the Vortech FMU - so adding another pound and a half of boost would be upping the fuel pressure 18 psi, and it's already maxing the stock fuel pump.
Also, my wastegate must be weird because I adjusted it down almost to the max you can adjust it, AND put a 1/8" washer between the wastegate bracket and the turbine housing to pull it even farther back and now it's just barely hitting 4.5 psi. I literally don't think I can get it up to 6 psi with this wastegate without a MBC.
Smart to be cautious.
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wait, i dont understand that statement. your wastegate actuator is attached to the turbine housing? Do you mean compressor housing? Also, how would putting a washer there increase boost? Maybe i am totally confused and misunderstanding you.
#7
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Yeah man, not even 5 psi and only 6 deg of timing is pretty damn weak. I would at least bump of the timing to 8 until you get a megasquirt. Also +1 on megasquirt and ebc, should solve all your problems right there.
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yeahhh mannn you should totally bump ur timing and increase boost cuz it'll b fasterzzzz, **** motor safety mannn
Ryan, you should be able to do more than 2.5psi. You may as well change the wastegate actuator now; I have heard that makes a huge difference. Your intercooler setup is sweet, BTW.
Ryan, you should be able to do more than 2.5psi. You may as well change the wastegate actuator now; I have heard that makes a huge difference. Your intercooler setup is sweet, BTW.
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wait, i dont understand that statement. your wastegate actuator is attached to the turbine housing? Do you mean compressor housing? Also, how would putting a washer there increase boost? Maybe i am totally confused and misunderstanding you.
Bump up your timing or you'll start melting ****.
Post pics of the IC setup.
About the actuator: can't find more than unhelpful mentions of upgrading the greddy actuator with the search function. Anyone have a link to info on a better actuator to throw on this thing?
-Ryan
#14
Check all your clamps. I had the same problem. I was getting low boost like 4psi even with the rod tightened so I checked all my clamps and one of them wasn't that tight. After i tightened it. I was boosting 6psi. If it makes you fell any better im running Greddy with IC at 6psi and timing of 9* and there no knock at all. Stock injectors and vortech but except I have a MBC and a BOV. But im telling you if you bump your timing from 5 to even 8 you will get alot of your low end back.
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the lower the timeing, the higher you EGT's, thats why Ben said you were going to melt ****.
Im running 10 psi with 10 degrees timeing, a vortec, and 305cc injectors. You can bump up the timeing with no knock.
Its ok to max out the fuel pump, ive been doing it for a long while, about 75ish psi it where it maxes out.
Im running 10 psi with 10 degrees timeing, a vortec, and 305cc injectors. You can bump up the timeing with no knock.
Its ok to max out the fuel pump, ive been doing it for a long while, about 75ish psi it where it maxes out.
#16
This is the main thread I know of for the greddy actuator upgrade, atleast it's the biggest one I know of.
https://www.miataturbo.net/forum/sho...eddy+wastegate
https://www.miataturbo.net/forum/sho...eddy+wastegate
#18
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ohhh, the wastegate actuator bracket is attached to the front of the compressor housing... it all comes together. Mine is attached to the back so, putting a washer in there would give me less boost.
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Ohhh never thought about the heat that would be generated from retarded timing! Thanks for the heads up.
I posted the pics of the intercooler:
https://www.miataturbo.net/forum/sho...183#post240183
And, here is a picture of my washer ghettoness with the wastegate actuator:
You can see the washers between the compressor housing and bracket, and you can also see that i have almost no threads left to tighten the rod down any more....
Maybe I have a loose hose somewhere...
I posted the pics of the intercooler:
https://www.miataturbo.net/forum/sho...183#post240183
And, here is a picture of my washer ghettoness with the wastegate actuator:
You can see the washers between the compressor housing and bracket, and you can also see that i have almost no threads left to tighten the rod down any more....
Maybe I have a loose hose somewhere...
#20
This is the main thread I know of for the greddy actuator upgrade, atleast it's the biggest one I know of.
https://www.miataturbo.net/forum/sho...eddy+wastegate
https://www.miataturbo.net/forum/sho...eddy+wastegate