Best Maximum boost pressure for a GTA Turbo ?.

Mythical figures both

[BIG_MVS]

WTF is Merlin and whos got a 390 bhp GTA?????

Come on Tony get with the programme.

I think the 390 bhp quote from Garcia came after a few too many Cruzcampo's and of course it was April the 1st you suckers!

Sorry hadn't looked at the forum much in recent months

Good stuff

Hi all,

My GTA has the Renix ECU upgrade, and supposedly has uprated boost pressure. Allthough it did not seem any different from other GTA's i had driven.

Paul, which Renix ECU upgrades are you referring? Can you please check and let me know. If it's the old buffered (op-amp) pot board (usually fitted on connectors bodged inside the ecu, but equally could be fitted externally), throw it away! It does more harm than good. I did explain this on another thread that phantom disappeared. But to explain, the bodge board changes the slope of the output of the map sensor so that it doesn’t hit the above mentioned reference voltage. Hence, it reduces the gain effectively (y=mx+c), and so for any actual pressure point the ecu thinks it’s seeing a lower actual pressure, and consequently cuts back the injection duty cycle – reduces the fuelling directly, not exactly what you want when you are most likely increasing the boost pressure. The fudge to this is then increasing the overall fuel rail pressure by fitting an adjustable regulator…. So the mess goes on… If you have one of those fitted, then I strongly suggest you take it off, and go back to std fuel rail regulator as well. There are better solutions, and just for ref there are some others that are supposed to be remaps, and they aren’t. Brodie Britain Racing (BBR) did a chip many years in the past, not too many floating around now, but fuelling isn’t ideal – two versions, and there have been some more recent ones. So it’s worth knowing what you have fitted exactly.

Well i removed my ECU today as i was having a bored moment.....
I was expecting to find some sort of piggy-back chip on the main board, but as you can see from the pics below. It looks completely standard.
So i guess i have a normal ECU after all ?.

Hi Paul,

Well I'm affraid (well depending on your point of view) that's a completely standard ecu. Nor does it have the boost cut disabled either. This is no bad thing, it hasn't been bodged or played with.
The reality is there were very few ecu's genuinely upgraded in the UK and I have collected those that I could find to scrutinise the modified files. The modified files, aren't really fully sorted anyway ( the variations enabled comparison and understanding of code sections), and all ran lean at high boost, I have the maps loaded into 3d files.
The Superchip upgrade did not in fact change the Map files in the Bipolar PROM chip - fuse link, burn once old technology, (lurking under the 211 stiker - software revision), nor did Prima from my best information. The upgrade was simply a waste gate bleed valve adjuster and some connecting hose, ecu just went on a nice round trip from the customer with no change being effected...
I have an old ART style board "up-grade" I pulled out of and ecu, I forget the source now, but if you really want to try it, then you can have it for the postage, my suggestion would be don't, better to do it properly but each to their own

Cheers,
Martin

Hi Martin,

Thanks for your detailed reply.

Im happy to leave it as is. My boost is bang on standard. Peaking at 0.85 bar, and tails off to about 0.7 bar at 5500rpm. (Shell V-Power)

Now the engine has been fully serviced, with new Air filter, new Fuel filters, platinum spark plugs, leads, dist cap, rotor arm, large cap oil filter, and 15/50 oil. She runs just great.
I would say its plenty quick enough, and lots of fun. Plus its 21 years old with 98,000 miles. So i dont want to over-stress the engine. Or as Lee pointed out, the head gaskets will more than likely let go.