I have a 20vt with basic mods, i.e air filter, exhaust, gtec 1 and upgraded spark plugs.

I'm wanting to go down the gt28rs route, however i want to make sure my engine can handle it before i do.

I've checked the compression and its fine, but do i take the oil pressure into consideration as well?

the oil pressures i've seen are:
lowest ever seen: 1.25
usual traffic idle: 1.25-1.5 bar
after a motorway drive: just below 2 bar
reving over 2500-3000rpm: 3bar

just to take into consideration i have changed the shells last year, but it didn't really make a noticeable difference in the oil pressure, and also i have a slightly bigger oil cooler.

so should I tune her?

My oil pressure has never been high - I quite often see 1.5 bar at very hot tickover, although its normally closer to 2 bar when the weather is cool.

You say you've replaced the shells - I assume this is the big ends (quite a bit easier than the crank journals). If this made no difference, I'd hazard a guess at your oil pump. My oil pressure was getting as low as 1 bar a couple of years ago, so Paul fitted a very good secondhand unit and the pressure immediately jumped by 0.5 bar

I'd say as long as you're seeing 3 bar on cold startup and also (when warm) when the revs are above 2,000rpm, you're fine.

To answer your original question, I'd say yes, tune it, but be aware of the slightly low oil pressure and tune it accordingly. Probably not a good idea to run it at 1.7 bar and definitely an excuse to make sure that you mod it properly.

To be honest, most failures caused by modding are down to incorrect fuelling or a basic lack of oil (ie simply not enough in the sump, rather than a low pressure)

The only thing I'd say with regard to taking the GT28RS route, is that in maximising the potential of the turbo (bigger injectors, 3" straight through exhaust, walbro, FMIC etc) you're going to be pushing the standard internals. You can of course use a GT28RS without pushing getting all of the supporting mods (as I am currently) but it'll mean a lot of the drawbacks of a bigger turbo (high boost threshold, more lag) without the advantages (big top end power).

If you intend to push a GT28RS to it's full potential, then budget for a forged rebuild. If you don't intend to go this far, then get one of the big hybrids.

Hi Hemz,

Just out of interest was the oil pressure the same before fitting the larger oil cooler?

The oil pressure reading could be wrong if your going by the standard gauge I know some have checked the oil pressure with after market gauges and seen much higher readings..... also I'm sure a few years back somebody got a garage to just tighten the sensor on the back of the engine, apparently there was a slight leak from there and tightening it gave a higher oil pressure reading...... if you're worried about it might be worth having the pressure checked properly to hopefully put your mind at ease!

Cheers
John

I went from a T28 hybrid to GT28RS as soon as I bought my coupe. I can't speak for the stage 3 hybrids, but I've never been disappointed with the RS.

You can't really refurb them though as it costs nearly as much as a complete new turbo. The hybrids on the other hand I believe is a lot cheaper to repair if something goes wrong.

The stage three hybrid will get you safe power on stock internals, is a straight fit, and will only cost a few hundred to re-furb. GT series turbo is not a stright fit, and if it needs re-furbing then you may as well buy a new one...

as far as tuning is concerned, just make sure that you know what you are doing, and that you dont scrimp on cost initially. It will bite you in the long run.

Look into the spec of the car you want, and budget accordingly - it always costs more than you think.

and do make sure you remap or it will go bang

thanks for the comments, just to answer johns question:



I think there was a slight drop in oil pressure after fitting the larger oil cooler, which i think is expected.

As far as tuning is concerned, i just realised i was running on low oil, and since I've topped it up its been at 1.75 bar on hot idle. so I guess I'll be tuning her, will be on the look out for gt28rs soon.

Just a thought, but once I've slapped on a bigger turbo, would i expect to see a slight drop in oil pressure, would the bigger turbo heat up the oil more?

MIGHT be selling my RSR soon.....good nik, low miles....