Couper

is it possible to put a turbo (even a small one) on a 7A engine?

scott12v@pghaudi

The real question is how much money do you want to spend. If it's not very much, then your answer is no.

Scott

Couper

you cant do anything to the 7A engine(as far as turbos).

Don@STaSIS

Howdy! At 10.5:1 or 10.3:1, can't remember, there is little room for boost. 2B is right in that regard. Though you can make a bastard 20v turbo with a 10v or 10vt block, slap on the 20v 7A head. The 10v NG/NF block and the 20v 7A head runs you down to 8.5:1 or so compression. The 10vt MC block and 20v 7A head runs you dwon to 7.5:1 or so, then it's a dog off boost.

Cheers,

cuatrokoop

Actually, the 20v head on a 10vt is at a MAX of 6.7:1 CR with the MC-2 block. The MC-1 results in a dern low 6.4:1 CR.

The NF or NG block will yeild 7.7:1 CR, and if you've ever driven a '86-88 5ktq, you'll know what it feels like before boost builds (its kinda laggy, but not terrible, I have one).

You COULD turbo the 7A, but you'll have to spend money on a small turbo either with an integral wastegate or external, new exhaust manifold, and gotta supply more fuel. However, boost would be very low, perhaps 7psi (absolute pressure) max if you are lucky. 5psi would be safer, but at that point, if you are after hp, why bother? For what you'd spend on the bits to do it, either put in a fairly well built up 10vt or a fairly stock 20vt, and be much faster than a cobbed together backyard special...

Don@STaSIS

Howdy! Wow it's even that low on the compression, yuck. I've never done the calculations with the 10v blocks and the 7A head, just going on what I've been told.

Thanks!

cuatrokoop

yeah, I have a nice little excel sheet I came up with...

The CR is a wee bit low ;-)

And the guy in Colorado wondered why his urq with a 10vt block and 20v head ran like poop! He had a "built-up" 10vt, and wanted a 20vt. So he "plopped" a 20v head on, and got the needed bits. Needless to say, he didn't pass emissions, nor did he have a very good idle. He messed with it for about a year, and gave up, went back to a 10vt setup.

putting a 20v head on a 10v/10vt block is something I am looking at doing, once I get the 10vt in and play with that for a while. I may push the 10vt to the limits first, then do the same with a 20vt, just because I can...20vt won't come for at least 2 years, I have to pay for a wedding first!

audineil

I don't want to seem picky but, 5psi or 7psi (absolute) is not absolute pressure but rather "gauge" pressure in this application.
Neil