I'm having an issue with my 250 not holding boost under full throttle in the midrange (3-4.5k rpm). Obviously there's turbo lag when I pin the throttle from 2k rpm but it will come on hard at 3k, then it feels a bit flat, wavy even. This is consistent, always between 3000-4200 rpm, then seems to pull smooth and hard to the red line. Does this on both maps, with tc on and off. Seems to only do this on full throttle. The dyno graph from EFI shows a wavy torque curve but I wouldnt have thought I would feel this as much? Something isn't right. Bought it in the pouring rain, previous owner failed it mention that it has a boost issue which he did know about. If you're reading this, Cheers pal. Apparently it's a 'characteristic' of the map (EFI) after I kicked up a fuss. Spoke to Chris, said the car left EFI with smooth power delivery after mapping early '22. Car is on 64k miles, Mods - Stock turbo stock cat mid Box chop recirc blank (just fitted) Ramair induction kit (just fitted) airtec intercooler 275bhp/300 310bhp /350 I've replaced the below, has made no difference whatsoever, not one bit - *NGK spark plugs IFR7X8G, 0.6 gapped *Spare green dot actuator *Renault /Beru coils *Renault N75 *Renault Injectors ultrasonically cleaned What could cause this, Any ideas? I have a fuel filter on the way to try. Someone mentioned map sensor? Graph here-
recirc blank (just fitted) Ramair induction kit (just fitted) Was this fitted before or after it started giving issues?
So essentially you car is loosing boost at its peak boost range. Could it be your boost pipes collapsing? are they the standard pipes? If you have standard pipes might be worth swapping for some samco type ones.
I once had very similar symptoms on my mapped R26. It was the O2 sensor. Doesn’t look like you’ve changed that so give it a go perhaps?
The only pipe that's not stock is an aftermarket Ikon solicone pipe that comes over the cam covers. Are there any reputable boost Hose kits for the mk3?
ive got the ikon ones, never had an issue. The pipe with the filter on, is this stock or aftermarket? youll be sucking in alot more air and those pipes do degrade so id swap that out for a silicone one.
Inlet pipe is also an ikon one, big Ram sir cone filter, new genuine N75 too. Trying a new fuel filter today
Still no solution- Fitted a new fuel filter and had the car in with a local garage for boost smoke test. They couldn't find a leak in the system and the car still has a dip in boost, same rpm range, 3k- 4k rpm. Then it clears and pulls hard and smooth to the limiter.. I've also replaced recirc valve, no difference. Booked in for Sports-cat and remap at Engine Dynamics in a few weeks, will report back.
