20v BT head on a 7AGE

[chadix24_7]

i currently have a 7AGE 16v with a tvis redtop head (MAP TYPE).

is there a gain by switching to a BT head?

[Dale]

edit: i was horribly wrong

[chadix24_7]

AFAIK it simply won't work, at least not without major modifications - feel free to correct me if I'm wrong

yeah it will work. but i need to know is the swap worth the gain?

[oldcorollas]

there will probably be gains from the smaller ports, but nothing you couldn't get from going to a non-TVIS 16V head perhaps?

if you want to use the TVIS to broaden powerband tho, then the 20V head is a better idea

[slide86]

I have a mate with a 7AGE 20v

With standard head and rebuilt engine, wolf 3d, exhuast and air filters it reeled of 110kw at the wheels. this was on initial tuning, i havent seen him for a few weeks. ill be interested on an update.

If thats the power you are after then it could be worth the gain, although aparently there was a bit a messing round with the setup to get it right. unsure of exact details tho....

[chadix24_7]

edit: i was horribly wrong

it's okay.

[chadix24_7]

I have a mate with a 7AGE 20v

With standard head and rebuilt engine, wolf 3d, exhuast and air filters it reeled of 110kw at the wheels. this was on initial tuning, i havent seen him for a few weeks. ill be interested on an update.

If thats the power you are after then it could be worth the gain, although aparently there was a bit a messing round with the setup to get it right. unsure of exact details tho....

is he still using the same porsche 924 timing belt?

[johnny]

is he still using the same porsche 924 timing belt?

I think you need to use a different belt as I think the 20V and 16V has different belt profiles.... Let me get back to you on Monday as I have both a 7AGE 16V and a couple of 4AGE B/Ts at work. Personally, the B/T head won't gain much over a good 100Kw head that has been re-build properly, and the 100Kw will cost you less to get more done to it.

[chadix24_7]

I think you need to use a different belt as I think the 20V and 16V has different belt profiles.... Let me get back to you on Monday as I have both a 7AGE 16V and a couple of 4AGE B/Ts at work. Personally, the B/T head won't gain much over a good 100Kw head that has been re-build properly, and the 100Kw will cost you less to get more done to it.

thanks, i'll be looking forward to that.

[Dimitri]

i can tell you for sure that the black top and silver top belts are differant. obviously if you go to the 11:1+ cr of the black top head/rod combo, over the 9.7 you have with your big port youre going to make power there.

[Jonny Rochester]

I am guessing the 110kw at wheels is with some fatter cams and reving well past 8? Harder to believe otherwise.

[johnny]

I am guessing the 110kw at wheels is with some fatter cams and reving well past 8? Harder to believe otherwise.

Fatter Cams. yes I reckon you'll need them, but Revving a 7A bottom past 7500, it ain't going to last very long with standard rods, so nice light weight A/M rods will be necessary and the crank and Flywheel will have be enrolled into the next Jenny Craig session... way too heavy to be revving that hard.

[Dimitri]

the bloke who does my wheel alignments has a 7a20 (silver top) in an IPRA ke55. he revs it to 9000 rpm when he races it. i think its done a whole season. the rods are definately said to be not up to par with 4ag rods.. but they can hold together it seems. nothing id bank on. if you have a 7a though maybe you wont need to rev it as haard anyway?