Trackday Turbo Project

[mfield 20]

I'm looking into my options for a new engine for my trackday car and wanting about 200bhp. So far i've ruled out most engines due to the factors of size/weight/cost/reliability.

 

But I've done a bit of searching on the forum and believe a combination of a xu7j4 bottom end/ xu9ja head with a TT manifold and turbo will give me a good balance of all the factors.

 

Factors involved:

 

1 : SIZE

 

The xu7 is more or less the same size block as the xu9. You might say why not use the xu9 then with the extra capacity, Age comes into it. I can go to a scrap yard and get a 50k engine for peanuts and use it till it dies, the xu9 is getting harder to come by with out it being corroded or some other fatal flaw that needs a re-build. The xu7 has a nice sump and counter balanced crank as std.

 

2 : Weight

 

It weighs the same'ish just got the weight of the turbo stuff which can't be that much more than the 16v iron block increase.

 

3 : Cost

 

The initial cost of the conversion will probably cost more than a 16v engine to get the same power, but when it goes pop it sould be case of swapping the bits over to another engine and away i go, if i pop the 16v engine the replacement cost goes up.

 

4 : Reliability

 

It should be fairly reliable due to not having major oil surge issues and a lower rev range, it will go pop at some point but alot of 16v engines seems to as well. When it does who cares , just get another block from the scrappy cheap.

 

Just idea's at the moment but opinions welcome

 

Oh and whats the cc of the head chamber on the xu9ja ? i've found the xu7j4 has 37.2cc and 10.4:1 compression. Just need to know if i can use the xu9 head and lower the compression abit then leave it at that or need more work doing.

[welshpug 1,626]

I think its 32cc.

[Powers 13]

Why dont you use the 2 ltr 8V head (xu10) as it has bigger valves and flows better than the 1.9 8v XU9. I am not 100% sure that this can be mounted to the xu7j4 bottom end though.

With the Xu10 head you can then use the turbo manifold from that engine which I am sure you can find for alot less money than the TT exhaust manifold.

[Tom Fenton 1,526]

The XU10 turbo manifold will also fit the XU5/9 head with no problem.

[Powers 13]

And will the XU10 head fit the XU7 Block?

[mfield 20]

And will the XU10 head fit the XU7 Block?

 

I'm pretty sure it will, plus iirc it will lower the compression nicely, so no need for skimming of pistons or other cheap mods

 

Will it seal ok for a turbo application having an 86mm bore ? Isn't there a copper gasket that can be used, i know the gasket is supposed to be the weak point for a reason but on a cheap engine i couldn't give a monkeys if it dies