View Full Version : N75 valve replaced - interesting!
ibizacupra
07-10-2002, 19:59
I had my N75 valve replaced today in an attempt to rid my motor of its 5psi moments...
Not had another 5psi event on my return trip from Cheltenham, but then again it is an intermittent fault after all! :(
Strangely the power delivery is quite different to before.
Dare I even say that the boost holds on longer !!!
Going to keep an eye on it from now and see if this is a real gain or just an illusion.
It could'nt be 13 months of sh1t I've been thru to turn up to be a poxy solenoid valve fault surely!!!!! Maybe I'm being premature but it does really drive quite differently.
Hmmmm.
I will wait and see.
Bill
Is it just a new N75 Bill or have you gone for the ECS N75 Race Valve.
Ive asked APR about this particular valve, only sent an email today, so not had my reply yet, but i expect it to be swift as always.
Its certainly interesting, id like to try it myself, as you know mine has had intermittent hesitancy, so am looking down this route myself.
im not surprised ;). had MAJOR boost missing with my first N75.
(remember i still got a spare new "C" valve if anyone needs).
Shock_Xe
07-10-2002, 23:32
Whats the difference with these n75 valves??? and how do they make a difference?? also how ££££?
From my experiences with different N75 valves (4 in total!), i have found that the C version delivers a lot more bottom end wheelspinning grunt but runs out of puff after 5K tailing down to 11psi past 6k rpm, whereas the F version starts off less brutal and takes slightly longer to build up boost but can hold 15Psi+ beyond 5500rpm and past 6k rpm it still holds 14psi
They both have totally different driving characteristics, I personally prefer the C version as the power is more explosive and has more initial overtaking grunt, but the F version is quicker overall and gives me a better 0-60 time too by around half a second
Originally posted by ibizacupra
I had my N75 valve replaced today in an attempt to rid my motor of its 5psi moments...
It could'nt be 13 months of sh1t I've been thru to turn up to be a poxy solenoid valve fault surely!!!!! Maybe I'm being premature but it does really drive quite differently.
Bill I was reading a lot of N75 stuff over on vwvortex (a of it Sim started! ;) ) and seems to make sense to me, there is one thread that is quite long on there and before reading it the wastegate/n75/turbo thing didn't make any sense to me - it is a lot clearer now (still I am only S/W engineer so this H/W stuff throws me). This is the URL for the forum (you probably have it, others might not) http://forums.vwvortex.com/zeroforum?id=27. It is worth reading in general because the USA seems to have done quite a few APR stage 3s.
On the subject of stage 3s and similar stuff (read jabbasport 300+bhp). Seems like if you push the engines too much (and they run lean) then they do go pop (not surprising). You going to be keeping a close eye on the A/F ratio when you get your turbo done?
Originally posted by Mosser
They both have totally different driving characteristics, I personally prefer the C version as the power is more explosive and has more initial overtaking grunt, but the F version is quicker overall and gives me a better 0-60 time too by around half a second
Mosser,
Very interesting! I got a "C" valve and it really explodes as you describe. Huge low down torque, wheelspin, wheelhop, but runs out off puff at 5k as you say. ;)
Changing the valve on my car fixed my power problems, the old valve was not faulty that I could see its just that the new valve works a lot better. This is after getting my cams swapped at Jabba. Mike however did not see why a new N75 could fix my problems. It has!
IMO the valve supplied with my car from new was of a bad batch.
Regards
Squiffy
Originally posted by Squiffy
Mike however did not see why a new N75 could fix my problems.
As it did for me too ;). My car is an AYP004918 (or something) engine code, built on 2001 october (regd. 2002).
ibizacupra
09-10-2002, 19:57
Originally posted by DaveP
On the subject of stage 3s and similar stuff (read jabbasport 300+bhp). Seems like if you push the engines too much (and they run lean) then they do go pop (not surprising). You going to be keeping a close eye on the A/F ratio when you get your turbo done?
thanks for the info.
Exhaust valves break and burn out on 20VT's when the mixtures run too lean.
regards
Bill
When stg 3 and (300+ BHP) engines "pop", they usually threw a rod and a hole in the block, no major problems with the head. However, a guy running nitrous has melted a plug which "fell apart" and did severe damage in the head. I also saw (personally) an unmodified TT 180BHP with 33k miles losing one of its plugs. Two valves and the piston had to be replaced - so make sure to replace your plugs BEFORE they should be originally replaced.
ibizacupra
09-10-2002, 22:53
Originally posted by Sim
When stg 3 and (300+ BHP) engines "pop", they usually threw a rod and a hole in the block, no major problems with the head. However, a guy running nitrous has melted a plug which "fell apart" and did severe damage in the head. I also saw (personally) an unmodified TT 180BHP with 33k miles losing one of its plugs. Two valves and the piston had to be replaced - so make sure to replace your plugs BEFORE they should be originally replaced.
Stick some decent ARP fasteners in there and they should last longer. Bolt failure most likely.
Exhaust valves are a weakness on 20V engines.
Bill
Shock_Xe
10-10-2002, 00:07
So what type of n75 valve is on a standard cupra?? c/f/other??? where do ya get different ones from and how £££
Mine came with a "C", others with "F". It's qutie random. It's available at official seat dealers. "C" is an old version which has been replaced with the "F" one. They cost the same ~65GBP (at least here where i live). "C" is not likely to be available tho, i got one spare left.
Bill,
Was your old valve a type C and your new one a type F by any chance?
I like the idea of holding 14psi+ over 6000rpm! :)
Ben
ibizacupra
11-10-2002, 21:44
Originally posted by BenS1
Bill,
Was your old valve a type C and your new one a type F by any chance?
I like the idea of holding 14psi+ over 6000rpm! :)
Ben
No idea mate.
Did'nt get to see the old part.
It does'nt run 14psi @ 6000rpm tho.
It does sustain the boost longer tho and now I have wheel spin where I never have had before!
Go figure.
Too early to tell as I still have'nt had time to drive it much. (messing with me Jetta lately)
regards
Bill
"It does'nt run 14psi @ 6000rpm tho."
I think beezers with the smaller K03 will never run 14psi @ 6000rpm (ECU controlled).
ibizacupra
16-10-2002, 14:43
Originally posted by Sim
"It does'nt run 14psi @ 6000rpm tho."
I think beezers with the smaller K03 will never run 14psi @ 6000rpm (ECU controlled).
Not so much ECU controlled Sim as mines chipped and this is one of the parameters it can set.... its more a case of it not being able to sustain that airflow at that rpm as well as the ECU winding back anyhow.
Bill
no, i meant remapped ECUs don't ask for such a high boost at 6000 RPM. if you get a manual boost controller (which im actually getting) you may set the nearly 1 bar and probably the small turbo will be able to deliver it. we measured ~0.98 bar at 6000 RPM with wastegate unhooked on the small K03. I'm not suggesting this high boost btw ;).
ibizacupra
16-10-2002, 20:47
Originally posted by Sim
no, i meant remapped ECUs don't ask for such a high boost at 6000 RPM. if you get a manual boost controller (which im actually getting) you may set the nearly 1 bar and probably the small turbo will be able to deliver it. we measured ~0.98 bar at 6000 RPM with wastegate unhooked on the small K03. I'm not suggesting this high boost btw ;).
Well... let me know if it can sustain it...
Melt melt melt melt. :p
Good luck.
Bill
hellspawn
21-10-2002, 18:13
When i took my car in to be chipped, it showed an intermitant engine fault, remember vince explaining that it was something to do with the boost not been high enough, and the car would have to compensate until the boost needed was reached, thus it would cause hesitancy, since the cars been chipped, can't say i notice it happening much any more, but it still does it now and again.
I wondering if after the experiences u have all been thru, its worth getting it changed.
As from the sound of it, it may cure the odd time's it plays up.
Yes, but dont expect the replacement N75 will be any better, quite some difference between these valves :/. Late 2001 models may suffer of a lower quality batch however.
Some people have tried the Dawes device and found it works well - http://forums.vwvortex.com/zerothread?id=511772
Shock_Xe
22-10-2002, 10:15
Ok this thing sounds good, dont think any1 has tried it on a beeza but they have on golf's and audi tt. They say it gets most noticeable gain on standard cars!!! Right so any1 interested in a group buy for this thing?????????
Bill did have a Dawes device on trial i think, dont know if he's still waiting or he had any success?
Bill?
Actually, I'm getting one right now. I did some research in this topic (mainly vwvortex) and they got mixed feelings.
In contrast with the ECU controlled N75 valve, the dawesdevices boost controller will deliver the same amount of boost (pre set value, up to 1 bar) no matter how you push that pedal. ECU's boost request is a lot more sophisticated way -- even when it generates hesitation and flat spots -- the requested boost is not a constant value, which you can't set on the dawesdevices BCS. They say, it's good for sprints and racing, but does strange things in the everyday driving. I'll use my "C" N75 for normal cruise, and dawesdevices for track/fun days and 1/4 mile runs.
Peek this:
http://forums.vwvortex.com/zerothread?id=511772
ibizacupra
23-10-2002, 14:21
Originally posted by Saul
Bill did have a Dawes device on trial i think, dont know if he's still waiting or he had any success?
Bill?
Got one yes..
Never tried it tho.... time is the enemy.
Bill
Bill,
if you'd took the procedure, you'd eliminate your 5psi moments in 10 mins ;). I'm expecting some robust and massive constant boost with the DD. I'm about to set it to 0.85 bar with a 1.5mm resctrictor before it (no N75), so i'll have a big spike (max boost) until 3500 then 0.85 bar up to redline. This may be something like a modded chip asks for.
Shock_Xe
23-10-2002, 21:00
Originally posted by Sim
Bill,
if you'd took the procedure, you'd eliminate your 5psi moments in 10 mins ;). I'm expecting some robust and massive constant boost with the DD. I'm about to set it to 0.85 bar with a 1.5mm resctrictor before it (no N75), so i'll have a big spike (max boost) until 3500 then 0.85 bar up to redline. This may be something like a modded chip asks for.
let us know how it goes??
im getting the controller in some days, but i'm not planning the "mod" for the winter to be the honest.