Max HP with standard internals?

What is the maximum HP I can push my GTO to without the need for pulling the engine apart? How would I achive this? I assume hybrid turbos, bigger injectors, bigger intercooler but does anyone have any specific advice? Also my dam cooling fans wont turn off anyone else had this issue?
Cheers Peter


@Permanent_Grin ran over 600hp on his standard block and internals , im sure he will let you know how he did it , that block is soon to live again as i bought it from him and is currently being rebuilt by someone else for their car

Craig :smile:

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I ran 560 on my previous gto for years with no issues.


Basically you are looking at bigger tubs , better fueling , pump, injectors etc , some form of piggy back ecu or standalone , boost control , certain cars will want for timing control , intercoolers will need to be upgraded etc

If i was spending all that , i would pull the engine and start forging to make it bomb proof , if you have bought tubs etc and your engine did let go then they will be as good as scrap anyway

Building one of these to run big and reliable horsepower isnt cheap , reliable is the key word here , hell i had a few goes at it :laughing: and still got bitten

Craig :smile:

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Craig has hit the nail on the head in my opinion. Getting to 600bhp on a standard block wouldn’t actually cost too much. Probably not a lot more money than going for the 450bhp mark. But it will always be a ticking time bomb. My advice would be to go for the 450-500mark if you are using a standard block. A pair of 13T’s and supporting mods will see you a nice 450 and that is plenty enough for a road car as it will keep a lightning quick spool.


I’m looking at doing exactly that @maxxbradley… I reckon that can be achieved for around the 2k mark using the standard turbos…fair comment? Or does anyone reckon I’m dreaming?


Standard Turbos UK 13G/11B will not do much more that 380-400 from pump fuel

9B are stretched at about 350BHP and no torque

Much more than 500 for a road car that will need to do mileage is asking for trouble

450-500 is quite hard to achieve with engine that done mileage.

If you build it with loads of 2nd hand or crap ebay parts it will go bang also

Justin your dreaming mate… lol


Hi guys. Today when i parked up my car a bloke came by and asked how much horsepower the drivetrain can handle on these cars. I wasnt sure what to answer at first, then i asked how much power he wanted and he said 600. I told him he would probably upgrade the drivetrain for that amount of power. So what do you reckon guys since we are speaking of tuning here? I got early MK1 car but i`m not gonna tunine the car, but just for curiosity? Lets base this topic on upgraded 25 spline box.

So @GSXRKID… Before you talk yourself out of selling any tuning parts :joy:… Let’s say I bought upgrade from 9b’s (not sure what’s best) an fmic, some sort of piggy back ecu, fuel pump an injectors… How much do you reckon it’ll roughly cost and what sort of bhp do you think it’ll push…? I have a mk1 that’s done 75k miles and is pretty much stock with usual exhaust n airfilter upgrade… . I drive her maybe twice a week, pretty hard, for an hour or 2 at a time… I want to increase power but really don’t want to pump thousands into an internal engine build…


You will see good figures with a piggy back , bigger fuel pump , injectors and 13t’s , you dont necessarily need a fmic i saw 450 on standard sidemounts and 468 on uprated sides , however what i will say is that a lot of the standard twin intercoolers now have seen much better days . I know one of the guys was running Maft pro 550’s fuel pump etc and 13ts on stock internals he saw a shade of 420 .

Best advice get a wish list and then ask opinions of what people have run and used , dont always use the given pre sold option

Craig :smile:

This is what I am running and have 430bhp. And there is probably a bit more in there. In my opinion it is the best option for a road car. Its very drivable and you can use all the power. And the spool is still almost instant!!

@justinmandeville here is a break down of prices taken from Robs website of the parts I have in my set up to give you an idea.

Maf-T Pro with boost control - 583.29
RC 550 Injectors - 399.62
Denso 277lph fuel pump - 166.63
Aeromotive FPR with gauge - 169.36
13T turbos - 999.95
Clutch - 500ish???..
I will ignore intake and exhaust etc. So including VAT you are looking at more like ÂŁ3k assuming you do all the work yourself. Plus mapping costs. Well worth it in my opinion.

All interesting stuff… I’m not to clued up on tuning but I can do most things with a set of spanners… So… Don’t laugh… No really don’t… But what if I did all of that n didn’t upgrade my insie winsie turbos…? Is it even worth doing…? The reason I ask is cuz like most folk I’m not made of money n would like to do things gradually. N with the twins being the most expensive, they would probably be last…

everything wears out a lot quicker when you start pushing it past what it was designed to do.

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As Gavin said. If you wanted to do the rest and gamble it then you would probably get 350 on 9b’s (GTO) maybe 380 on 11b’s (3000GT). But you would be better off buying it and leaving them off the car and then saving again for the turbos and doing it all at once.