Upgrading in 2023 - what is the state of the art? and help request

[Marxus]

Hello all!

As I own my VR4 now for some time.. ~ 6 years, finally the time has come do to something to it. To give you some idea of where I want to go to (in relation to foxdie's post): At least to the downpipes in the long term, camshaft I don't know how and don't understand the principle yet, would skip. And if it makes sense at that point maybe the injectors, but no further.

Now there is a lot of information already on this website and on ozvr4, but some of the guides and discussions were quite old.
What really makes me wonder is, that in the very past, everybody said "you need a 3"catback before doing anything else + IC".

And then I read foxdie's sticky and.. its simply not mentioned? Only a de-cat pipe, but de-cat is illegal here. Aiming for a Hi-Flow cat because that I could get probably arranged. Getting a 3" cat-back will be .. tricky. New exhaust must not be louder than the original one and I still need to check how to get this legally done without having a complete emissions test cycle (~4000 Euros) done. So I need to re-evaluate based on the infos I will receive on this post. I do totally understand that a bigger exhaust would be beneficial and is more a necessity if I want to put bigger downpipes on it as the factory cat-back system would bottleneck them + the hi-flow. Any statements about upgrading to 2.75"?


Boost control solenoid: Is there a big difference between a new stock one and the Perrin? Couldn't find much information about this. Will the stock one be sufficient for my plans? Or would you always choose a aftermarket over the stock one for XX reason?

And would you, from todays point of view, add anything to that list or change anything on it? I mean, the list is from 2016.


Now my "personal" requests:
Health of the car seems not too bad. Engine mounts look good, I get some knock while shifting under WOT (think it was a knock count of 2 when shifting from 2nd to 3rd) but none during acceleration itself. After wintertime, the car will have the following upgrades including stuff that has already been done:

- Intercooler
- New TME lifters
- TME Steve clutch upgrade
- Hi Flow cat
- wideband O2
- Pipercross air filter
- Spark plugs + ignition leads
- Metal BOV from an Evo
- New boost solenoid (either stock or aftermarket, depending on the answers here)
- Walbro upgrade (is it already necessary to hotwire it by then? OZVR4 TME Steve is not a fan of hotwiring it, at least he wasn't from that older posts)
- MAYBE a bigger cat-back, depending on the circumstances, have a hole in my stock exhaust where I can easily put my finger into it, without the rest of the rust being removed. (this is a very uncertain point)

So, having someone remote to contact about ECU tune (Cable is on its way!) would be awesome, willing to pay of course. Like, a tutorial at home at first during winter time and maybe another short session with tips when at the dyno, details probably better to be settled via PM. Already found an 4WD dyno in my area as well.

So.. thanks for reading and very keen to receive your replies!

Kind regards

[Confused]

Yeah, the old stickies could do with some updating...

An engine is essential an air pump - so the quicker you can get air in, and subsequently out, with minimal restrictions, is going to net you the most improvements, and if you can cool that air down to be as dense as possible, you get the most oxygen atoms you can.

A higher flowing exhaust will allow the gasses to escape quicker, as will a high flow cat, again minimising pumping losses, and less "power" is being sapped by trying to push this air out.

I guess the question is how far do you think you want to go? But, as quick responses to your list...


- Intercooler - a 600x300x76 generic intercooler is an upgrade to the stock one, and fits without much faffing
- New TME lifters - if you have ticking, then yes, worthwhile to replace them - I replaced mine with ones from Viamoto, this cured my ticking
- TME Steve clutch upgrade - if you don't want to change to an Evo flywheel and clutch, opening up a huge variety of possibilities, then this is a reasonable alternative
- Hi Flow cat - as mentioned before, any removal of exhaust restriction can only help
- wideband O2 - a must, IMO, but not all are created equal
- Pipercross air filter - NOT a cone/pod filter, though - these mess up the airflow characteristics into the MAF, causing odd fuelling issues, and they suck in warm air from the engine bay.
- Spark plugs + ignition leads - the biggest issue nowadays is age of the standard coil packs, a Coil On Plug conversion would benefit here more than spending money on leads
- Metal BOV from an Evo - if your stock one is leaking, then sure, this is a suitable upgrade
- New boost solenoid (either stock or aftermarket, depending on the answers here) - at this age, a lot of stock solenoids are failing, stuck closed. Plus, a 3-port one gives a bit more resolution in control, and ability to push boost a bit higher for any given duty cycle
- Walbro upgrade (is it already necessary to hotwire it by then? OZVR4 TME Steve is not a fan of hotwiring it, at least he wasn't from that older posts) - potentially some older pumps didn't like being speed controlled, and the flow at lower voltage was not sufficient before it stepped up the supply voltage. I've run a Walbro 255 at full voltage and with a decent FPR, it maintains the desired pressure - maybe it's heating the fuel slightly at this...?
- MAYBE a bigger cat-back, depending on the circumstances, have a hole in my stock exhaust where I can easily put my finger into it, without the rest of the rust being removed. (this is a very uncertain point) - again, any removal of restriction in the exhaust helps.


As for ECUs, and tuning... the money spent on the Tactrix cable, and the time spent on a dyno to start the car, do something, stop the car, make a change, flash the change, start the car, get back and check the change will be just as much, if not more, than simply going with an aftermarket ECU, which can do live tuning. If you're starting to push more, then you'll also want the advanced engine protection strategies that an aftermarket ECU can provide - full wideband O2 reading & corrections, fuel pressure monitoring and compensation, oil pressure monitoring and protection strategies...

I know many people (such as TME Steve) does have success with the stock ECU, but there are limitations, it is old technology, and if you're a tinkerer, it's substantially easier with a modern ECU.


With all this being said, I'm a hobbyist, TME Steve does this stuff for a living...

[Marxus]

Thanks a lot for that information.

So basically the Magnecor leads I bought 5 years ago were a waste of money? Back then (until now tbh) I was convinced COP mod is only useful when trying to go insane with power. Same goes with ECU. But of course what you say makes sense.. as the dyno times with stock ECU will be much longer than with aftermarket I guess? But I checked a few ECUs that are mentioned here an on ozvr4 and phew.. 1400 - 2000 for that ECU is a hefty price tag (probably reasonable, though but for a newbie it sounds like a lot for a little piece of electronic). But I also read that the stock ECU is only capable of controlling its default 6 sparks, does a COP system then even make sense when I am not able to control each spark individually with the stock ECU?

Since I am here a bit on my own (I only know one other VR-4 driver here) I also fear that messing with an aftermarket ECU will exceed my tinkering skills by far at this point. Thats why I had the idea of getting all the mods done, and a little remote help to get a little bit into ECU tuning and a guiding hand so I don't blow up my engine. I watched those 16 videos for ECUFlash (links here in the forum do not work anymore too btw, but they are still around on youtube) to see whats the point behind all this, read into it here a lot and felt like "yep, can do that with little help, probably also on my own when going slow, but help is always appreciated". Would post that into the service wanted area when the time has come.

To be honest, in the beginning I wanted a few extra horses for little money with bolt on mods and a tune. But I fell down a rabbit hole I think.

Now, thanks to your reply, I also see no way around but to convince wifey that the hole in the exhaust cannot be fixed... (a shame ) Already found a used Legalis R. Will try to get my hand on that, but its an 11 hours drive. In one direction A used one will not raise that much attention during "our" MOT, as long as emissions are okay.

Not important for the topic but I should have clarified more:

What is installed:
- Lifters + Clutch - 3 montsh after I received my car, a seal blew (crankshaft seal i think? sorry english is not my native language), covering my clutch in oil. Just bought the clutch from steve and ordered lifters as well, as the ticking was driving me nuts.
- New sparks + leads - car came with totalled spark plugs. Just realized after I had the clutch incident. Had failures during high load before, maybe that lead to the seal fail?
- BOV -> could get my hand on one and took the chance, just to be sure.

Whats lying around, waiting for installation:
- IC is already waiting for installment, Mishimoto S-Line
- wideband -> bought the spartan one.
- air filter -> nope, not a pod. I did my homework and ordered one that fits into the standard box

What still has to be ordered
- Hi flow + cat back
- boost solenoid -> was not sure if to by a new stock one or aftermarket, would have made that dependent on the price. But since you said the aftermarkets are more "responsive", probably I will go with a aftermarket one
- Fuel pump: Already decided to go with DW200, Still looking for a FPR. Will follow your recommendation and hotwire it (bypass the resistor)

Again, thanks, and always appreciate more input if you have some