Built motor @ 17psi misfire
#41
![Default](https://my350z.com/forum/images/icons/icon1.gif)
Thanx alot for your help man I really appreciate it.
I see what your saying about the fuel, I am using the stock fuel rail which has the dampers on it (Dont know how good those are). I actually purchased a fuel rail so that I can make my own plumbing but the rail does not fit (it hits the upper manifold, its a fwd manifold). But for sure I agree with you its something that should be upgraded if is the source of the problem.
I briefly went over my wiring and couldnt find anything that might cause a problem, all grounds look good, everything looks great. (i took my time wiring the emanage so i know thats perfect.).
I just lowerd the boost to 15psi, and let me tell you, the car pulls alot harder, pulls all the way to redline and it didnt misfire. Now this leads me to the following, you mentioned about checking the air intake. Can having an intercooler thats too small cause such problems?
I see what your saying about the fuel, I am using the stock fuel rail which has the dampers on it (Dont know how good those are). I actually purchased a fuel rail so that I can make my own plumbing but the rail does not fit (it hits the upper manifold, its a fwd manifold). But for sure I agree with you its something that should be upgraded if is the source of the problem.
I briefly went over my wiring and couldnt find anything that might cause a problem, all grounds look good, everything looks great. (i took my time wiring the emanage so i know thats perfect.).
I just lowerd the boost to 15psi, and let me tell you, the car pulls alot harder, pulls all the way to redline and it didnt misfire. Now this leads me to the following, you mentioned about checking the air intake. Can having an intercooler thats too small cause such problems?
If you checked all of your wiring, especially your grounds, and it is not an issue with your spark plugs, I would lay odds it is in your fuel return system. If it were me, I would configure the fuel return system like AAM's system as shown in the link I sent you. If your new fuel rails won't fit, then borrow an intake plenum from someone that will clear the fuel rails.
If you cannot find one locally, I have a VQ35DE intake plenum. I was not planning on selling it, but I will let you borrow it. I'll ask for a deposit just to make sure I get it back. I live in the West Palm area. If you want to make a trip up to borrow it, let me know.
#42
![Default](https://my350z.com/forum/images/icons/icon1.gif)
I don't think so. Do you have T-clamps or work type clamps? Some people have had problems with T-clamps when the ends of the pipes are not sufficiently rolled. Anyway, that is a really, really long shot based on the description of your problem. If that were the problem, it should be popping up alot more.
If you checked all of your wiring, especially your grounds, and it is not an issue with your spark plugs, I would lay odds it is in your fuel return system. If it were me, I would configure the fuel return system like AAM's system as shown in the link I sent you. If your new fuel rails won't fit, then borrow an intake plenum from someone that will clear the fuel rails.
If you cannot find one locally, I have a VQ35DE intake plenum. I was not planning on selling it, but I will let you borrow it. I'll ask for a deposit just to make sure I get it back. I live in the West Palm area. If you want to make a trip up to borrow it, let me know.
If you checked all of your wiring, especially your grounds, and it is not an issue with your spark plugs, I would lay odds it is in your fuel return system. If it were me, I would configure the fuel return system like AAM's system as shown in the link I sent you. If your new fuel rails won't fit, then borrow an intake plenum from someone that will clear the fuel rails.
If you cannot find one locally, I have a VQ35DE intake plenum. I was not planning on selling it, but I will let you borrow it. I'll ask for a deposit just to make sure I get it back. I live in the West Palm area. If you want to make a trip up to borrow it, let me know.
Id have to look up how the maxima guys rig up the RWD manifold on our FWD vq35de since it does run into the hood, I believe they have to cut or modify the manifold somehow, and in that case, I wouldnt be able to borrow yours ofcourse, and not sure if im ready to buy it yet. We'll see on friday. ill keep you updated, n thanx again
#46
![Default](https://my350z.com/forum/images/icons/icon1.gif)
I would assume a restrictive muffler will just cause boost pressure drop, but dont know if it would cause reversion
#47
New Member
iTrader: (11)
![Default](https://my350z.com/forum/images/icons/icon1.gif)
no way he's blowing out his spark with that lil meth nozzle, esp with that tiny spark plug gap.
Its only a 440cc nozzle. I'm running at least a 600cc (9.5 gph) nozzle (might be bigger) on mine at less boost.
Only feasible if his pump is taking a **** and is not atomizing his spray. I'd pull that out of the equation for now anyhow.
Its only a 440cc nozzle. I'm running at least a 600cc (9.5 gph) nozzle (might be bigger) on mine at less boost.
Only feasible if his pump is taking a **** and is not atomizing his spray. I'd pull that out of the equation for now anyhow.
#48
New Member
iTrader: (18)
![Default](https://my350z.com/forum/images/icons/icon1.gif)
no way he's blowing out his spark with that lil meth nozzle, esp with that tiny spark plug gap.
Its only a 440cc nozzle. I'm running at least a 600cc (9.5 gph) nozzle (might be bigger) on mine at less boost.
Only feasible if his pump is taking a **** and is not atomizing his spray. I'd pull that out of the equation for now anyhow.
Its only a 440cc nozzle. I'm running at least a 600cc (9.5 gph) nozzle (might be bigger) on mine at less boost.
Only feasible if his pump is taking a **** and is not atomizing his spray. I'd pull that out of the equation for now anyhow.
![Big Grin](https://my350z.com/forum/images/smilies/biggrin.gif)
#49
![Default](https://my350z.com/forum/images/icons/icon1.gif)
no way he's blowing out his spark with that lil meth nozzle, esp with that tiny spark plug gap.
Its only a 440cc nozzle. I'm running at least a 600cc (9.5 gph) nozzle (might be bigger) on mine at less boost.
Only feasible if his pump is taking a **** and is not atomizing his spray. I'd pull that out of the equation for now anyhow.
Its only a 440cc nozzle. I'm running at least a 600cc (9.5 gph) nozzle (might be bigger) on mine at less boost.
Only feasible if his pump is taking a **** and is not atomizing his spray. I'd pull that out of the equation for now anyhow.
#51
![Default](https://my350z.com/forum/images/icons/icon1.gif)
Although holset does not release flow maps, this might be accurate:
![](http://www.dsmtuners.com/forums/attachments/turbo-system-tech/78378d1197242946-holset-turbos-part-3-hx35.jpg)
Exhaust housing is 12cm with t3 inlet and 3" outlet, and compressor wheel I think is 54mm with 4" inlet and 2.5" outlet.,
#52
Registered User
iTrader: (2)
Join Date: Nov 2005
Location: NYC
Posts: 2,252
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
I see, well in my setup I have dont have any cats or even resonators. all I have is the muffler after the turbo (Dynomax Superturbo 3" in/out) which I think its really restrictive.
Although holset does not release flow maps, this might be accurate:
![](http://www.dsmtuners.com/forums/attachments/turbo-system-tech/78378d1197242946-holset-turbos-part-3-hx35.jpg)
Exhaust housing is 12cm with t3 inlet and 3" outlet, and compressor wheel I think is 54mm with 4" inlet and 2.5" outlet.,
Although holset does not release flow maps, this might be accurate:
![](http://www.dsmtuners.com/forums/attachments/turbo-system-tech/78378d1197242946-holset-turbos-part-3-hx35.jpg)
Exhaust housing is 12cm with t3 inlet and 3" outlet, and compressor wheel I think is 54mm with 4" inlet and 2.5" outlet.,
Edit: I looked at the map again and it is not terribly bad as I initially thought.. It will be nice to stay within the middle of the map though...
Last edited by athenG; 09-24-2009 at 08:05 AM.
#53
![Default](https://my350z.com/forum/images/icons/icon1.gif)
With a VQ30 which is about 182 cid and and assuming 2psi lost on the piping/intercooler, then you will need about 1.31bar (19psi) to hit 1.17bar on the manifold (17psi). After doing the numbers on a 182cid (3.0L) engine, you will need a turbo that can pump at least 44lbs/min at 6200rpm. If you map is accurate then your turbo is a little small and way past its efficiency range at 6200rpm and 2.3bar. At 17+psi you need at least a 60-1.
Edit: I looked at the map again and it is not terribly bad as I initially thought.. It will be nice to stay within the middle of the map though...
Edit: I looked at the map again and it is not terribly bad as I initially thought.. It will be nice to stay within the middle of the map though...
Either way, I think for now, I am going to stick with 15psi. I am going to upgrade my charge piping and intercooler. I have alot of pressure drop, a 13psi spring gives me about 5-6psi (not good), and this is getting the WG reference from the turbo. Thats about 8psi of pressure drop, mostly due to the intercooler perhaps and a few silicone bends (that might be getting pinched, ill have to see. I have had the same chargepiping setup since day one (3 years ago), so its probably overdue for an upgrade.
#54
![Default](https://my350z.com/forum/images/icons/icon1.gif)
If thats the case, the map might not be accurate, reason being is that there are guys running this turbo at 27+ psi (4 bangers @ 400-550whp), based on alot of searching I have done, it is said the turbo flows 60lbs/min (dont kno at what rpm).
Either way, I think for now, I am going to stick with 15psi. I am going to upgrade my charge piping and intercooler. I have alot of pressure drop, a 13psi spring gives me about 5-6psi (not good), and this is getting the WG reference from the turbo. Thats about 8psi of pressure drop, mostly due to the intercooler perhaps and a few silicone bends (that might be getting pinched, ill have to see. I have had the same chargepiping setup since day one (3 years ago), so its probably overdue for an upgrade.
Either way, I think for now, I am going to stick with 15psi. I am going to upgrade my charge piping and intercooler. I have alot of pressure drop, a 13psi spring gives me about 5-6psi (not good), and this is getting the WG reference from the turbo. Thats about 8psi of pressure drop, mostly due to the intercooler perhaps and a few silicone bends (that might be getting pinched, ill have to see. I have had the same chargepiping setup since day one (3 years ago), so its probably overdue for an upgrade.
#55
![Default](https://my350z.com/forum/images/icons/icon1.gif)
60 lbs/min is a maximum flow rate, and is not tied to a specific rpm. In other words, at whatever rpm your engine needs 60 lbs/min, the turbo should be able to provide assuming you have enough exhaust gas flow at that point to turn the turbines fast enough. That rpm at which your engine starts consuming 60 lbs/min. will primarly depend on the engine's displacement and the boost setting. The rpm will be inversely related to these.
Note: just to point it out, my intercooler is 26" x 5.5" x 2.25"
Last edited by streetzlegend; 09-24-2009 at 11:12 AM.
#56
Registered User
iTrader: (2)
Join Date: Nov 2005
Location: NYC
Posts: 2,252
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
60 lbs/min is a maximum flow rate, and is not tied to a specific rpm. In other words, at whatever rpm your engine needs 60 lbs/min, the turbo should be able to provide assuming you have enough exhaust gas flow at that point to turn the turbines fast enough. That rpm at which your engine starts consuming 60 lbs/min. will primarly depend on the engine's displacement and the boost setting. The rpm will be inversely related to these.
#57
![Default](https://my350z.com/forum/images/icons/icon1.gif)
+1 you cant compare a 4 banger vs a 6cyl because the bigger displacement will consume more air than a smaller engine at a given rpm. That is why a turbo should always be matched to the engine displacement and power level expectation. I think that turbo is great for 4cyl and high boost but may choke on a V6 and
Last edited by streetzlegend; 09-24-2009 at 03:08 PM.
#58
![Default](https://my350z.com/forum/images/icons/icon1.gif)
IF (and I mean only if) the wiring and spark plugs have been eliminated as potential issues, and there are no issues with boost creep or boost leak, then the fuel retun system is the most likely candidate.
Anyway, if you are happy with your present boost level, then it really becomes a non-issue.
Last edited by ttg35fort; 09-24-2009 at 03:32 PM.
#59
![Default](https://my350z.com/forum/images/icons/icon1.gif)
Update:
So i changed the plugs, I did have 1step colder already as I previously mentioned but i put in a new set, I gapped them at .030 and have my ignition at 16v (same voltage i had before). I did a few little things here and there, I had the injectors grounded on the same wire as the voltage booster device (which is a pretty thick wire that goes to the battery, so I just ran seperate grounds for the injector and the device. changed a few bolts for the upper manifold (which weird thing was that after starting the car, my idle and part throttle was very rich so I had to retune, perhaps I had a vac/boost leak at the manifold from the old bolts/stud not providing enough torque since it was stripped)
I did a few 2nd gear runs and did not feel a misfire or hesitation, took the car all the way to 6200 and nothing. this was at 15psi in 2nd gear, I let the auto get into 3rd and instantly pulled hard and boost jumped to 17psi. The car feels pretty strong now. Perhaps is was the grounds, or the old plugs had been through too much meth (i had a 10gph nozzle before which was overkill, and had dipped the AFR into the 9's alot). The base of the plug where the threads are were basically black, the ground straps were like in the pic on the 1st page.
So. it seems to be solved, for now I am going to keep the boost where it is, and next, upgrade IC and piping from IC to motor.
So i changed the plugs, I did have 1step colder already as I previously mentioned but i put in a new set, I gapped them at .030 and have my ignition at 16v (same voltage i had before). I did a few little things here and there, I had the injectors grounded on the same wire as the voltage booster device (which is a pretty thick wire that goes to the battery, so I just ran seperate grounds for the injector and the device. changed a few bolts for the upper manifold (which weird thing was that after starting the car, my idle and part throttle was very rich so I had to retune, perhaps I had a vac/boost leak at the manifold from the old bolts/stud not providing enough torque since it was stripped)
I did a few 2nd gear runs and did not feel a misfire or hesitation, took the car all the way to 6200 and nothing. this was at 15psi in 2nd gear, I let the auto get into 3rd and instantly pulled hard and boost jumped to 17psi. The car feels pretty strong now. Perhaps is was the grounds, or the old plugs had been through too much meth (i had a 10gph nozzle before which was overkill, and had dipped the AFR into the 9's alot). The base of the plug where the threads are were basically black, the ground straps were like in the pic on the 1st page.
So. it seems to be solved, for now I am going to keep the boost where it is, and next, upgrade IC and piping from IC to motor.
Last edited by streetzlegend; 09-25-2009 at 09:09 PM.