Fuel cut defenser=Blown 13b?
09-02-11, 03:50 AM
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Fuel cut defenser=Blown 13b?
Hey guys, I have a complete racing beat turbo 2 exhaust package on my 87' FC.
I still have the restrictive stock airbox but I have plans to replace I soon with an aftermarket intake and install a fuel cut defenser as well.
I read on another site that this combination; the fuel cut defenser+intake+exhaust will cause the factory turbo to spool faster and pump more air than the stock fuel system can handle. This of course will cause a lean mixture resulting in a blown engine. They said that either a fuel computer upgrade or adding additional injectors or larger ones is some of my options; along with a bigger fuel regulator, heavier duty fuel pump ect.
Is this true? If so what are the best economical solutions to this potential problem? Any advice is appreciated.
I still have the restrictive stock airbox but I have plans to replace I soon with an aftermarket intake and install a fuel cut defenser as well.
I read on another site that this combination; the fuel cut defenser+intake+exhaust will cause the factory turbo to spool faster and pump more air than the stock fuel system can handle. This of course will cause a lean mixture resulting in a blown engine. They said that either a fuel computer upgrade or adding additional injectors or larger ones is some of my options; along with a bigger fuel regulator, heavier duty fuel pump ect.
Is this true? If so what are the best economical solutions to this potential problem? Any advice is appreciated.
09-02-11, 05:56 AM
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I think the cheapest solution is to skip the FCD and simply buy a RTek 1.7 or 1.8 chip that has a FCD function, and install a Walbro 255 LPH fuel pump and upgraded fuel injectors that are supported by the RTek.
http://www.pocketlogger.com/index.ph...age=1&ecu=S4T2
http://www.pocketlogger.com/index.ph...age=1&ecu=S4T2
09-02-11, 11:15 AM
#5
Just having the exhaust will cause boost creep without a ported wastegate. You don't have to have an intake to cause boost creep. RTEKs (and even spare ECUs to send off for them) are rediculously cheap. Depending on your power goals, etc, you might just want to go straight to a RTEK 2.1 so you (or your tuner) have the ability to really tune your fuel as you modify the car.
09-02-11, 12:05 PM
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A high-output fuel pump is a separate issue.
Ah yes, that would be a cheaper option to the Walbro if the OP doesn't plan on running much boost.
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09-02-11, 12:12 PM
#8
Oh it's definitely cheaper to get a FCD and fuel pump, but the fuel pump is not enough to keep you from popping a motor. If you intend to continue modifying the car, and to make use of those mods, then you're going to need a way to tune fuel anyway. Might as well do it sooner rather than later. A RTEK is only $400 new (you can find them used on occasion for between $200 and $400).
Edit: Sorry, I have a habit of disregarding the Stage 1 RTEKs. They are certainly valuable, and still better than a FCD (and comparably priced), but if you're gonna go RTEK, might as well go all the way.
Edit: Sorry, I have a habit of disregarding the Stage 1 RTEKs. They are certainly valuable, and still better than a FCD (and comparably priced), but if you're gonna go RTEK, might as well go all the way.
09-02-11, 04:13 PM
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the first one is boost cut, stock boost is in the 6.5psi area, boost cut is about 8psi, the RB exhaust by itself should have you touching about 10psi. the FCD clamps the pressure sensors signal, so it can't go over 8psi (i think its 8.25, but whatever). the Rtek does the same thing, its just inside the ECU, and it adds a couple of other features.
the second problem is fuel. the stock fuel pump flow is exactly equal to the flow of the injectors when they are wide open. this leaves no margin for old fuel filters, old wiring, low voltage (the wire that supplies voltage to the car has a STAPLE holding it together), or pump age. its pretty mandatory to upgrade the fuel pump. the stock FD pump is good, you can usually just go over to a friends house and grab it. the walbro is good too.
the other side is that the stock ECU is only programmed to deliver fuel to a STOCK engine, and it has a little margin, at some point you've increased power by something like 20%, and fuel needs to be increased too. this is where the Rtek makes a lot of sense, as you can either buy the bigger injector model, or buy the 2.xx which is tunable.
i've done it a few different ways, i feel the bigger fuel pump is mandatory. i always did some kind of fuel control (fcons actually) and with those the bigger injectors are optional below 10psi. without fuel control, you might need more injector sooner
09-02-11, 04:21 PM
#10
A FCD is about $100-120 new, and it requires an aftermarket boost gauge which is about $50-150, for a total of $150-270. An RTek ECU upgrade is $120-150, has a built-in FCD function, does not require an aftermarket boost gauge, fixes the 3800rpm stumble, eliminates the AWS function, retards the timing at higher boost levels, and adds a flood clear function to the S4 cars. I see no reason to buy a FCD.
A high-output fuel pump is a separate issue.
Ah yes, that would be a cheaper option to the Walbro if the OP doesn't plan on running much boost.
A high-output fuel pump is a separate issue.
Ah yes, that would be a cheaper option to the Walbro if the OP doesn't plan on running much boost.
And if you can find me a Rtek for $120 be my guest.
09-02-11, 06:27 PM
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FYI when you see an underlined, funny-looking line of text on this forum, it usually indicates something called a "hyperlink". You can click on it with your mouse or whatever you younger guys use on your cell phone, and it will take you to another place on the internet where you can find additional information.
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09-02-11, 09:06 PM
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What size secondary injectors do you recommend? My power goals are somewhat mild, I would like to be able to push my stock turbo setup as far as I can without the risk of damage.
I am on a buget so I am trying to do this without putting me to far in the hole. I would like to push it to about 300whp. Is that a practical power goal or is that wishful thinking? If it is practical what all would I need to do without having to port my motor? Thanks to everyone for their input in taking the time to respond, it is very helpful.
I am on a buget so I am trying to do this without putting me to far in the hole. I would like to push it to about 300whp. Is that a practical power goal or is that wishful thinking? If it is practical what all would I need to do without having to port my motor? Thanks to everyone for their input in taking the time to respond, it is very helpful.
Last edited by Clark13b; 09-02-11 at 09:09 PM. Reason: Forgot to say thanks
09-03-11, 07:50 PM
#16
there is no limitation on that exhaust except for the upper ranges which you are far from.
limitation on the engine/fuel setup is about 10 psi with the chip, stock turbo and stock injectors before you will need a wideband to check for safety AFRs, which will put you at about 220ish WHP.
to get to 300WHP you will need to do alot more research and save a few more shiney pennies. the stock turbo will not get you there.
limitation on the engine/fuel setup is about 10 psi with the chip, stock turbo and stock injectors before you will need a wideband to check for safety AFRs, which will put you at about 220ish WHP.
to get to 300WHP you will need to do alot more research and save a few more shiney pennies. the stock turbo will not get you there.
09-03-11, 08:24 PM
#18
Do yourself a favor get the rtek before you do anything else. I did the mistake on my s5 TII rebuild only had 30k on it. full exhaust no cat air intake stock turbo everthing else stock. figured id get a fcd later just baby it till then. well a little impatience down shifted to 4th to go around someone not thinking and ping ping boom cracked rear seal and now need another rebuild. So again get the rtek and theeeeen modify basicly give your self a strong platform to start with.
09-04-11, 01:01 PM
#20
1.5 is fine as well but for higher boost levels you'll need the larger injectors which means 1.7/1.8, if you need to pull the EGI fuse more than once or twice a year to deflood an engine then you have more serious issues to worry about than whether you need the clear flood feature in the first place.
IMO the benefit is slightly better than throwing in an FCD which is an ECU trick and causes incorrect ignition timing. anything over 10 psi even with the Rtek chip requires certain safety measures to be sure the fuel system can handle it. either way i don't suggest pushing over 10psi with the stock ECU(and Rtek chip upgrade) anyways, as you greatly begin risking your motor after that point.
IMO the benefit is slightly better than throwing in an FCD which is an ECU trick and causes incorrect ignition timing. anything over 10 psi even with the Rtek chip requires certain safety measures to be sure the fuel system can handle it. either way i don't suggest pushing over 10psi with the stock ECU(and Rtek chip upgrade) anyways, as you greatly begin risking your motor after that point.
Last edited by RotaryEvolution; 09-04-11 at 01:06 PM.
09-04-11, 01:33 PM
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What size secondary injectors do you recommend? My power goals are somewhat mild, I would like to be able to push my stock turbo setup as far as I can without the risk of damage.
I am on a buget so I am trying to do this without putting me to far in the hole. I would like to push it to about 300whp. Is that a practical power goal or is that wishful thinking? If it is practical what all would I need to do without having to port my motor? Thanks to everyone for their input in taking the time to respond, it is very helpful.
I am on a buget so I am trying to do this without putting me to far in the hole. I would like to push it to about 300whp. Is that a practical power goal or is that wishful thinking? If it is practical what all would I need to do without having to port my motor? Thanks to everyone for their input in taking the time to respond, it is very helpful.
This website has a pretty good build list, but it is a little bit outdated. The newer Rtek option supersedes the outdated FCD, and is a good replacement for the aftermarket fuel computer up to the point that you exceed the fuel flow of 4x720cc injectors (roughly 300bhp). Some people go with a fuel computer after that, but personally I think it is better to skip the mid-level mods and go to a full standalone EMS at that point if you have the time and money. You can also go to the Mods,Main page to see the common modifications for these cars.
http://fc3spro.com/TECH/FM2W/power.htm
The above link also does not include the BNR turbo upgrade option, which is a good low-budget method to make more power. They also have pretty reasonable prices on stock rebuilding and wastegate porting if that is all you want.
http://gonzaloherrero.com/bnr/index....d=67&Itemid=89
You didn't know much about the subject, nor how to use the internet. Now you know more about both. Get over it. Sheesh. This forum isn't a contest.
09-04-11, 01:43 PM
#23
I know it's not a contest. I'm not making it one. However you say it's cheaper to go a 1.7 than a fcd. Yet with the 1.7 you don't add the cost for bigger injectors and you say someone needs to buy a $150 boost gauge if they go fcd. Okay. Suuuuure.
I think I will look into using the Internet more. I can sit on the forums all day like you seem to do.
I think I will look into using the Internet more. I can sit on the forums all day like you seem to do.
09-04-11, 09:24 PM
#24
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Hey, I like the links you posted. The turbocharger website is just what I needed. I'm thinking of a bnr stage 2 or stage 1 hybrid turbo exchange. My stock turbo is blowing oil into the throttle body, I needed a turbo rebuild anyway, why not upgrade?
