Some DOubts I have for a long time.
04-19-2005, 12:40 PM
#1
1.0 BAR
Thread Starter
Join Date: Apr 2005
Posts: 375
Some DOubts I have for a long time.
This pertains to stuff Ive read on HMT. Again and again.
First. Why the distaste for FMU or raising rate fuel regulators.
Its this distaste for your Honda EFI cars or all cars. My setup is carbed and I dont see a way arround using a FMU / regulator.
The use of a restrictor in the oil feed line to the Turbo.
Im not using one and the car is smoking a lot mainlly white smoke.
The thing is it could probally be an issue with the oil return line.
But as per corky bell. THe oil pressure should be 5 PSI idle and 25 psi full load.
I dont have a restrictor should I put on in.
When the engien is started there is a short spike of 70 PSI this settles down to arround 20 PSI under normal operation.
Havent done many miles on the car. Maybe under 50 do you think I could have blown the seals. What kind of seal does the IHI RFB5 use.
My mates turbo which is off a disel has no oil seal. Just a piston steel like washer.
But his setup wasnt ball bearing.
First. Why the distaste for FMU or raising rate fuel regulators.
Its this distaste for your Honda EFI cars or all cars. My setup is carbed and I dont see a way arround using a FMU / regulator.
The use of a restrictor in the oil feed line to the Turbo.
Im not using one and the car is smoking a lot mainlly white smoke.
The thing is it could probally be an issue with the oil return line.
But as per corky bell. THe oil pressure should be 5 PSI idle and 25 psi full load.
I dont have a restrictor should I put on in.
When the engien is started there is a short spike of 70 PSI this settles down to arround 20 PSI under normal operation.
Havent done many miles on the car. Maybe under 50 do you think I could have blown the seals. What kind of seal does the IHI RFB5 use.
My mates turbo which is off a disel has no oil seal. Just a piston steel like washer.
But his setup wasnt ball bearing.
04-19-2005, 02:16 PM
#2
3.0 BAR
Join Date: Jan 2003
Posts: 4,438
Re: Some DOubts I have for a long time.
because with the high accuracy of efi using somthing as vauge and untunable and unreliable as an fmu is just a waste. Using somthing even like uberdata and 450cc injectors doesnt cost much more and the tuneabiity and performance is worth it and reliable, plus most efi people ive ever seen generally start leaning out at like 6-7psi boost... thats garbage. FMUs work on carbs just fine... but who needs 100+ psi fuel pressure efi wise?
04-19-2005, 03:11 PM
#3
1.5 BAR
Join Date: Apr 2004
Posts: 995
Re: Some DOubts I have for a long time.
If you are using carbs I don't know what other options you have...
The reason FMUs are bad is they raise the fuel pressure according to boost level. So, if you are in boost at say 10lbs from 4k to 8k, the FMU is pushing the same pressure, so, when you first hit boost it might be too much fuel and at the top of the RPM range you could lean out...
I don't know much about carbs though. But I remember it talking about carbs a lot in Maximum Boost, which it sounds like you have been reading.
About using an oil restrictor, there are a lot of oppinions... if your turbo is already smoking, I would at least try a restrictor and see if that helps the problem before you go out and spend the money on a rebuild...
The reason FMUs are bad is they raise the fuel pressure according to boost level. So, if you are in boost at say 10lbs from 4k to 8k, the FMU is pushing the same pressure, so, when you first hit boost it might be too much fuel and at the top of the RPM range you could lean out...
I don't know much about carbs though. But I remember it talking about carbs a lot in Maximum Boost, which it sounds like you have been reading.
About using an oil restrictor, there are a lot of oppinions... if your turbo is already smoking, I would at least try a restrictor and see if that helps the problem before you go out and spend the money on a rebuild...
04-19-2005, 03:30 PM
#4
3.0 BAR
Join Date: Jun 2003
Posts: 3,975
Re: Some DOubts I have for a long time.
when does it smoke? all the time? high rpm? under boost?
a generalization is that white smoke is usually water. blueish is oil, and black running rich.
throw on a header and see if the smoke is still there.
a generalization is that white smoke is usually water. blueish is oil, and black running rich.
throw on a header and see if the smoke is still there.
04-19-2005, 03:49 PM
#5
1.0 BAR
Thread Starter
Join Date: Apr 2005
Posts: 375
Re: Some DOubts I have for a long time.
It started smoking after I installed the turbo and toped up the oil.
We felt maybe the oil was draining under the oil. So I disconected the oil return line and let any oil in the pan drain out.
Then put the hose back on. The smoking droped a lot.
We then did presure test of the oil line.
RIght now on startup it seems fine but if you take it for a longish ride say 10kms or more. She starts smoking. Its white smoke but you can definetlly get the smell of burning oil.
There is no shaft play what so ever. In any direction.
I will try the restrictor.
My oil stick has two dots on it. At present the oil level is just a tad above the first Dot. Is this ok.
How do I chk for water in the system. Could be a head gasket leak or could it also be watter leaking at the turbo since its a watter cooled turbo.
I see no drop in collant, though the oil level does seem to be droping.
We felt maybe the oil was draining under the oil. So I disconected the oil return line and let any oil in the pan drain out.
Then put the hose back on. The smoking droped a lot.
We then did presure test of the oil line.
RIght now on startup it seems fine but if you take it for a longish ride say 10kms or more. She starts smoking. Its white smoke but you can definetlly get the smell of burning oil.
There is no shaft play what so ever. In any direction.
I will try the restrictor.
My oil stick has two dots on it. At present the oil level is just a tad above the first Dot. Is this ok.
How do I chk for water in the system. Could be a head gasket leak or could it also be watter leaking at the turbo since its a watter cooled turbo.
I see no drop in collant, though the oil level does seem to be droping.
04-19-2005, 05:06 PM
#7
1.5 BAR
Join Date: Aug 2003
Posts: 1,194
Re: Some DOubts I have for a long time.
With a carb in a blow through application, an FMU is not even an option. You want a 1:1 regulator to keep a steady fuel pressure in relation to boost pressure.
FMUs are stupid because with a fixed ratio (say 10:1 or 12:1) they will only supply the right amount of fuel at one point in the map, the rest will be too rich or too lean.
An FMU is a cheap way to blow up an expensive motor, and should never even be considered an option. Why do you think people who buy turbo kits blow up their engines every single time? Because those stupid kits cut costs on engine management by including an FMU and some don't even have spark timing correction. Spark timing is much more important than air-fuel ratios. You can get away with AFR deviations but you will not get away with having the spark timing a couple degrees off.
FMUs are stupid because with a fixed ratio (say 10:1 or 12:1) they will only supply the right amount of fuel at one point in the map, the rest will be too rich or too lean.
An FMU is a cheap way to blow up an expensive motor, and should never even be considered an option. Why do you think people who buy turbo kits blow up their engines every single time? Because those stupid kits cut costs on engine management by including an FMU and some don't even have spark timing correction. Spark timing is much more important than air-fuel ratios. You can get away with AFR deviations but you will not get away with having the spark timing a couple degrees off.
04-19-2005, 05:07 PM
#8
1.5 BAR
Join Date: Aug 2003
Posts: 1,194
Re: Some DOubts I have for a long time.
Originally Posted by baldur
With a carb in a blow through application, an FMU is not even an option. You want a 1:1 regulator to keep a steady fuel pressure in relation to boost pressure.
FMUs are stupid because with a fixed ratio (say 10:1 or 12:1) they will only supply the right amount of fuel at one point in the map, the rest will be too rich or too lean.
An FMU is a cheap way to blow up an expensive motor, and should never even be considered an option. Why do you think people who buy turbo kits blow up their engines every single time? Because those stupid kits cut costs on engine management by including an FMU and some don't even have spark timing correction. Spark timing is much more important than air-fuel ratios. You can get away with AFR deviations but you will not get away with having the spark timing a couple degrees off. And to back that up, I run about 14.3:1 AFR at 5psi, because that's just cruising and I don't want to waste fuel there. 15psi is where the action is at.
FMUs are stupid because with a fixed ratio (say 10:1 or 12:1) they will only supply the right amount of fuel at one point in the map, the rest will be too rich or too lean.
An FMU is a cheap way to blow up an expensive motor, and should never even be considered an option. Why do you think people who buy turbo kits blow up their engines every single time? Because those stupid kits cut costs on engine management by including an FMU and some don't even have spark timing correction. Spark timing is much more important than air-fuel ratios. You can get away with AFR deviations but you will not get away with having the spark timing a couple degrees off. And to back that up, I run about 14.3:1 AFR at 5psi, because that's just cruising and I don't want to waste fuel there. 15psi is where the action is at.
04-20-2005, 11:58 AM
#9
1.0 BAR
Thread Starter
Join Date: Apr 2005
Posts: 375
Re: Some DOubts I have for a long time.
The first car is runing 14 PSI for months now with a Home made FMU and has actually gone on a long cross Interstate ride to see how it behaves.
Im still confused. Are you guys knocking FMU for EFI or for carbs.
Can you recomend an optimum FMU to use on a blow trhu setup.
Thanks.
Im still confused. Are you guys knocking FMU for EFI or for carbs.
Can you recomend an optimum FMU to use on a blow trhu setup.
Thanks.
Thread
Thread Starter
Forum
Replies
Last Post
RotaryGeek
Forced Induction
32
01-22-2008 10:34 AM
