Iv just got a mk4 golf gti turbo (my first turbo car) and im looking for a dump valve upgrade, I understand that I cant fit an atmospheric dumpvalve as the 1.8T uses a resirculating valve. iv done some research online and found the forge split valve and I wondered if there is any other valve similar to the forge valve that will fit my golf? any help would be appreciated as I am a noob shane
If it's standard I wouldn't spend too much @ 0.6 boost your gonna be the only one hearing the discharge :-/
Manual control boost valve- frowned upon by some, but if fitted correctly and used for moderate gains can be- from what I've read- quite successful :-/ I'm fitting one in a couple of weeks so I'll let you know There is also an upgrade for the N75 valve, being an N75j, also resulting in a higher boost. I may be fitting one of these the week after if the MCBV doesn't work out ha ha High flow air filters and exhausts are also options, however I've done both and noticed very little difference, apart from sound. Probably the best option if you have the dollar is a remap :-) but depending on year it can be more expensive as the ecu has to be removed on earlier models and flashed on a bench.
Well, fitted the new N75j valve today, not quite what I expected but there is a slight increase in power around the midrange rev band. I tried fitting it both ways as suggested, but found the correct way made the most difference, making the loom a little tight when the plug is on. Considering the little difference it had made, I'm going back to my original train of thought- I have a leak somewhere in the pipe work :-s have seen a little oil from time to time under front off side wing, suspect intercooler seals have failed :-( I'll take a look next week.
As the boost on these is controlled electronically via the N75 solenoid, If you try to increase the boost via mechanical bleed valve or tightening the pre-load on the wastegate actuator the ECU will back off the power anyway. remap should be first port of call.
The n75j doesn't raise boost does it ? It just delays the gate opening doesn't it? No gain just holds boost slightly longer and spools earlier.
What I mean is, if you try to raise the boost by other non-standard means, other than a remap the ECU will stop you from doing so.
Ah I see, is that the same for a manual boost controller with a bleed valve? Bypassing the N75 by looping it on itself? Fooling the ECU into thinking N75 is down? I was at a tuning shop the other day, but got sent away as my ecu had to come out to remap it and the guy didn't have time :-( it's a 1999 AGU
