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Discussion Starter · #1 ·
Sorry about the NEWB post, but ive read the Faq, and after the arguing i got some info out of it.
My familiarity is in Nissan and other imports, and this is my first stab at the VW so here goes..
what is the difference in the 1.8t used in every VW/Audi compared to the 1.8 used in this 93 fox?
are the oil pans, and exaust manifolds(bolt and gasdget) simmilar?
Id like to use the T3 flange manifold but if cost efficant ill go elsewhere
turbo, if T3 or K03 both arnt a problem locating
downpipe
gti intercooler
intercooler piping
MBC
oil/water/vacuum lines
main questions :
How much boost is safe? Im not looking for a NHRA drag car, friends car, wants to be quicker and woop up on rice rolling arround town and have a BOV to impress the ladies.. im thinking 4-6lbs
whats the compression?
how is the bottom end on holding boost?
is the EFI smart enough to cope with the added air, or is a FPR needed
once again, sorry for the newb post, and this isnt my first Turbo car. Ive worked on so many turbo cars, and converted so many that it drives me nuts. I have my aged copy of Maximum Boost right here. and im ready for some CONSTRUCTIVE criticism
 

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Re: Turbo Fox questions. (Hat1324)

4-6lbs?
WAY more than that. You could run 15lbs pretty easily with a efficiant IC (does not mean huge, just well designed) and probably up to 18lbs with some good tuning.
Bottom end is very strong. But, I would recomend 8-10 lbs for daily driving and still having a good time.
I would start reading the forced induction forums.



Modified by HiJinx at 1:42 AM 1-14-2004
 

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Discussion Starter · #3 ·
Re: Turbo Fox questions. (HiJinx)

well the FAQ is a bit brief and jumbled.
Ive decided on using the T3 manifold, and going with a T3 I can pick off a old 300zx real eazy.
my only problem now is the fuel system and the oil pan.
Will the 1.8T oil pan bolt to this block? if not ill have to drill a hole and weld a fitting on.
What would be a good location to T Split a oil line for the entrance to the turbo?
and do you think the stock ECU will be able to cope with the boost, or will I need to use a FPR or afc?
thank you for your help!
 

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Re: Turbo Fox questions. (Hat1324)

What year of Fox is it? It makes a big difference if you're trying to do this on a CIS-E car or a Digifant car.
No, the 1.8T oil pan will not fit. That oil pan is made for a transverse motor as I recall rather than longitudinal. Nothing with the Fox is going to be just a matter of bolting up the parts, though next weekend I'm sending word to Brazil that Gol turbo parts would be in demand in the US so we can see what that turns up.
 

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Re: Turbo Fox questions. (Ol' Grey Fox)

A 1.8T oil pan from a Passat or Audi A4 is a perfect fit. But you really don't need one. You can find a QTD oil pan or just drill and bolt on or weld on a fitting for oil return.
The QTD has an oil supply on the filter flange. That seems like a good place.
If it's a 90 or earlier Fox, CIS-E will provide for enough fuel up to 150 or so HP with perfect reliability as long as you know how to tune it. 200 HP is the ceiling. If your car is Digifant (91 and later,) sell it and buy another Fox. Digifant is dangerous in stock trim with a turbo. Lean out is very likely.
 

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Discussion Starter · #6 ·
Re: Turbo Fox questions. (FrankenFox)

wow, that was totaly not what I wanted to hear.
yeah its a 93 and selling it isnt a option.
what is the problem with it?
someone told me I could just use a 4bar FPR and be fine.
and another question. Why do the restrict exaust gas? that seams like a step backwards if you ask me.
 

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Because it was originally designed to be a very economical car - a putt-putt mobile if you will - and I guess they realized how much real power this car was capable of and thought to give it a bigger exhaust as an upgrade in hopes of increasing sales? That's my guess...
 

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Re: (noodle32)

My theory on why the Fox was purposefully downtuned is that the Jetta was VW's flagship and while it weighed a good deal more than the lowly Fox, it had the same basic motor and thus would be quite easily embarrassed in a test of performance. To keep the highest end car from getting smoked by the lowest it seems a reasonable step to restrict the exhaust, which gives the added advantage of dropping the powerband slightly to deal with those tall gears.
The rest of the Fox's anti-performance issues can be chalked up to a desire for improved economy. The small valves, mild cam and lack of WOT or knock sensor all go out to building a car for less money that will use less fuel, a trend that continues right down to the heavy flywheel to help with constant speed driving.
Yes, the Fox got the shaft when it comes to performance, but no other VW of the era that I've been in can boast the 30 mpg mixed driving even new, much less 15 years after it rolled off the assembly line. (2 weeks until my car's 15th birthday, still getting 27.6 mpg city in stock mechanical trim)
Be bright side of all this though is that we have a wide selection of factory parts on which to draw for building a performance version of our beloved Fox. Dasher exhaust, modified A2/A3 springs, 16v 'Rocco brakes, etc. The sad part is that the Digifant system is so integrated and crippled by these choices toward economy that it's really quite worthless for tuning and you're better off grafting in either a CIS, a Jetta/Golf Digifant rig or a standalone system rather that try to tune what is already near the end of what it can do.
If selling the car is not an option and you really want to go performance (especially forced induction) then I would suggest something along the lines of MegaSquirt to fuel your car.
 

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Re: Turbo Fox questions. (Hat1324)

Quote, originally posted by Hat1324 »
what is the problem with it?
someone told me I could just use a 4bar FPR and be fine.
and another question. Why do the restrict exaust gas? that seams like a step backwards if you ask me.

You definitely haven't been around VWs long enough--cars in general, really. It's all about steps backward. Everything VW has done since 1992 or 1993 onward has been a step in the wrong direction.
In 1991, VW brought Digifant II injection to the Fox. Digifant II is a tolerable fuel system, but it quickly runs out of fuel and is intolerant of conditions too far outside the original design. A 4 bar FPR will help a lot. But the Fox's Digifant system has non-knock sensing ignition, which is a BAD thing under boost. The system simply does everything it can to do the wrong thing for performance--whether that means too much timing, too little timing, too little fuel. Other Digifant II systems can be chipped. But most chip makers/computer rebuilders suck. Nobody makes anything that is universally accepted, and chips are almost NEVER custom-tailored to your needs.
CIS-E is adjustable to just about anything you can throw at it up to about 180 HP. Beyond that, it can provide more fuel, but drivability suffers due to CIS-E's limited range of self-adjustment. In other words, if you set it up to supply 200 HP worth of fuel, it will be unable to supply only 40 HP worth of fuel for puttering down the road.
 

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Re: Turbo Fox questions. (FrankenFox)

Knock sensors are crap and almost completely useless under boosted situations. They don't even work untill it's too late...after the engine has already detonated. Not sooo bad under NA aps, but say you have 18lbs of boost and detonate, the damage has already been done.
It's all about tunning.
Digifant is complete crap. If you are seriously concidering running boost, run CIS, or get a stand alone. Digi can't make up it's mind on what it wants to do, especially if it's being driven hard. It will flake out, lean out and generally ruin any tuning you have done.
 

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Discussion Starter · #11 ·
Re: Turbo Fox questions. (HiJinx)

ok, well from the book ive been reading. The only problem is really in the control unit. But im thinking of just switching straight to a SAFC or a AFR. or a FPR.(id like to go with a electronic unit, due to its RPM controlability, as well as its TP adjustment) I have most of the list complete. And as soon as the list is done Im pretty sure its going to happen.
Ive found alot of sources for most of the parts, including the manifold.
the List:
Manifold atp 8vT3 : lets just say less then listed...
T3 turbo(off Z31) : $100
S13 SR20 IC : $75
oil pan(welding flange for oil fitting) :$6.00
intake AND exaust piping :$50
SAFC AFR FPR : anywhere from $50 - $200
oil/water lines (20') :$5
vac lines (20'):$5
craploads of clamps :$10
silicon bends(for intake piping,10'):$30
oil T : $3.00
water Ts :$5
cant think of anything else...
 

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Re: Turbo Fox questions. (Hat1324)

instead of running just apexis safc i would consider running an sds (simple digital systems) injection system, though it is a slightly more expensive system and is really farther in-depth tuning, rather than just plug-n-play. but if you know all that you say you know i am sure you can figure it out. this will also rule out the somewhat restrictive digi maf sensor and replace with a 4 bar map sensor. as far as spark i would consider using an msd ignition to control and tune spark and timing in accordance with the sds, plus this a relatively cheap and cost-effective tuning tool, you may also want to get a knock sensor from another digi jetta or golf and tt's aluminum knock sensor bushing to work in conjuction with the two. Finally i would use a dial-a-boost boost controller, you can put one of these in cabin giving you the simplicity of changing boost from the drivers seat rather than under the hood, plus it is extremely less expensive than apexi avc-r, or a profec-b or anything along those lines. There are basically 4 components to make an engine run; air, fuel, spark and compression, and with this setup you can almost completely control 3 out of 4 of those factors. In addition to these parts to make this a more reliable and worthwhile system and less taxing on the components that will be controlled by these systems, i would say to use a 4 bar fpr and either stock or upgraded corrado g60 injectors, also i know of a machine shop who sells a hiflo billet 8v fuel rail and i believe eip does too. for the air coming i would use new vacuum hosing, silicon if feasible, and possibly a g60 cam or turbo cam of some sort, and a tt (techtonics tuning) adjustable cam gear. if at all possible use a gti big valve head in conjuction with this cam and upgraded valve springs. have your intake manifold extrude honed and your tb bored, then have the head portmatched to your intake and exhaust manifolds for the best flow possible. the spark issue can be taken care of with the msd and upgraded plug wires, i recommend blue igniters, and either ngk iridium plugs for a g60 or bosch platinum 4+s.
but it seems like you know a lil bit about what you are doing and possibly have a fair amount of money to move so i suggest doing something different, something new, something no one else has ever done before. I would like to suggest to you twin charging your fox. This can be a useful power adder in conjuction with everything already in use with the turbo system...you will of course need a few more items but you may find this useful. you will need a g-lader supercharger from a g60, the two mounting brackets (one that connects to the alternator bracket, and one that connects to the oil dipstick) more intercooler piping, another open element air filter, another line from your oil source and another goin to the oil pan, and finally the belt that goes from the timing belt to the blower. this is the simplest way to do this and will be completely insane with a turbo, the supercharger providing low end boost, reaching from 8-10 lbs by 2000 rpm, and then another 10 lbs kicking in fully around 4000 rpm, this would be nuts with a 7500 rpm redline via the sds, msd, and hi-rev head. Now this is the simplest way to do this but i would also recommend either a small top mount intercooler just for the supercharger or a small air-to-water intercooler for it, but this is not completely necessary bcuz the blower does not get as hot as a turbo because it doesnt deal with hot exhaust gases. I have a drawing of how this would work if anyone is interested i would scan it and put it on here, it is very rough but it explains well...
I understand that these are all opinions of mine that i have formulated but i see no reason why these would not work to make a near if not over 200hp on the stock bottom end. I have spent many a sleepless night thinking about how to do this and have thought out nearly every avenue of this and come up with a good plan to make this work well.
 

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Discussion Starter · #14 ·
Re: Turbo Fox questions. (MYFoxIZhot93)

wow, thats alot of information.
Such has the head/cam swap. It will remain stock. This will not be a car looking for high numbers at all.
A simple profec B will be used in car.
Id like to upgrade the maf, but at this venture I think in will handel the low boost.
would you use the 4bar FPR in conjuntion with the fuel controler?
rubber, $0.25 a foot vacuum hosing from a hookup at advanced auto parts.
you listed a Gti cam, but arnt all Gtis 16v+?
thank you for reminding me on the new spark plugs, but currently while still at 10lbs im staying away from MSD.
FOX-N-IT:
sorry,
1st gen BOV :$45
still undecided on the standalone, either AFR or SAFC
and prob a handy autometer boost guage.
i think thats it, and it all needs to be presented...more info to follow, thank you everyone for the help.
 

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Re: Turbo Fox questions. (Hat1324)

btw this is my new sn formerly myfoxizhot93
anyways i had mentioned a big valve head from an earlier gti, early to mid 80's there were 8v gti's, basically a golf but two door and i believe the higher like 10:1 compression ratio, rather than the fox's 8.5-9:1 cr, and i was saying using a cam from a corrado g60 (which is a 1.9litre 8v, similar to the fox) with a tttuning adjustable camgear, bcuz of the different overlap and lift.
You can use the 4 bar fpr with a fuel controller bcuz there is actually no electrical signal going to the fpr, how much fuel goes into each cylinder is controlled by a signal from the fuel injector harness. Here is an example: say your computer is adaptive and you have a 3 bar fpr on your car, now you get to a point where the car need 1 bar of fuel pressure to each injector, this is decided and signalled to the fuel rail by the harness at the end of the fuel rail. What happens is vacuum will change and your fpr will be pushed to its maximum usage point and each cylinder will only get .75 bar of fuel pressure, if it were evenly distributed but most likely the first 3 will get 1 bar and the last will get nothing and you will detonate... its not so much about a signal going to your fpr as it is about minimize injector duty and fpr duty that is y upgrading all these parts accordingly when properly tuning your engine is a must... i hope this made sense and helps out...
also you may be in luck if you are interested in a few of these parts because i have a fully rebuilt big valve head that was on my car for about an hour of run time, it has oversized valves and hilift heavy duty valvesprings. I also have a g60 cam and tttuning blue anodized adjustable camgear that i will be selling...




Modified by taPassVR6 at 4:16 AM 1-21-2004
 
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