998 Turbo - Standard head
Turbo Mini Forums

Hi all, Hope this hasn't been asked before!

Who is running a standard 998 head on their turbo project....?

What mods have you done to it? I have a spare kicking about so I have been considering having a hash at it with the die grinder, instead of buying a cooper casting :)

Thanks, Al

Ask Benross he'll be your man but it should be fine if the compression is dropped

They flow poorly, but if you're on a budget & must use one then have a look in Vizards big yellow book, mods to this head are covered extensively.
For Turbo use, as a minimum I would round off the beak in the chamber, it's far more pronounced on the 998 heads than the 1275, & I've seen several standard heads cracked from this point. It's definately a hot spot.
Phil.

Edited by Turbo Phil on 21st Aug, 2012.

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OK, maybe I'll have a think....

I'm not quite sure what to do yet - I just thought seeing as I had a spare I'd have a go at modifying it!


Need to have a think about how to mount the bits up too - I don't have the bulkhead problems that most have :)

But I don't know really if that is to my advantage

Edited by wagon_rider on 21st Aug, 2012.

Get yourself a 295. Even in standard form they are far better than a lightly modified 998 head. Just change the exhaust valves for some one piece ones.

I made a nice road motor by using a standard head and grinding the chambers to a better shape. Ran a T2 and 8 psi of boost. Needed a bit of refining but worked well.
Went for 12G295 in the end though and enjoy a lot more top end but have sacrificed the low end for it.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

I don't believe that the 295 was the reason for loosing low end torque. Could it be something different?

Does anyone have any patterns for modding a 12G202, looking for something similar cc as a 295 maybe a bit bigger?

“A turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.” - Jeremy Clarkson

'spose an extra £100 for a 295 on top of everything is small beer really!

MJ is my next purchase.... Perhaps I need to get a project thread on the go about this!

The problem with 295's is finding a usable one for sensible money.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Does anybody have any pics of standard 998 heads with mods please? :)

We're having a problem finding a 295 for not stupid money too. It's making me consider other options that might be available instead of shelling out £150 for a head that still needs work and parts to fit it. Just wondering if could you get enough meat out of a 940 to use on a 998t engine? for something around 80bhp not the usual 100odd people aim for.

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=537811

12G295 in her which just wants refurbishing for £145. To me this seems like a good deal.

If something is worth doing, it's worth doing half of.

imo depending on what your after i believe if your prepared to have someone that really knows there stuff do a head and spend the time then to start with a 202 as you have the opatunity to have good high speed ports and nice bowl/valve seat same for the chamber shape you can get it how ever you want it i think most of this is aplicable to a low rpm high tourqe engine ie small ports have high air speed but dont flow to well at high rpms