Compression Ratio

[morningstarr86]

What would be the best compression ratio for a NA Blacktop with a 7A-FE block?

[oldeskewltoy]

What would be the best compression ratio for a NA Blacktop with a 7A-FE block?

What are you planning on using this for? What engine management do you intend to use?

Stock blacktop is 11 to 1... no reason you can't use that as a basis to build the stroker

[morningstarr86]

I was planning on using the stock ECU and I'm gonna run the engine in NC with my dad. He told about a the local races they have down there. If I'm not mistaken I think its a road course.

[oldeskewltoy]

not knowing enough about the character of a stroked blacktop... I'll assume for now the stock ECU is capable...

the likely problem you will encounter is building the crank and rods... the stock 7A parts are not known to withstand high rpm stress loads well, even race shops tend to limit 7A builds to under 9000 rpm and that is with custom crank AND rods.....

What is your intended budget?

[morningstarr86]

My budget is roughly 5400 after the purchase of the blacktop. I found C-Rods from Crower. I'm not sure were to get the crank shaft. I would like it to be capable of 10,000 RPMs. What do you think and custom pistons fron JE Pistons?

[MisterJerk]

is ths your first ae86? If it is, recommend you to go with the rebuilt stock 4age with the regular bolt ons(if its allowed in the class you plan on racing), Intake, header, exhaust. Decent suspension, coilovers, or trd shocks n springs, if you a millionaire. Stock power levels on this car is very fun and will help you get to know the chassis and upgrade as your skill grows.

[yoshimitsuspeed]

You will definitely want to pay attention to racing rules and classes. If they have a more stock class you may have more fun and be more competitive than in a heavily modified class.
If everything goes though or if you can do more within the same class then I say go for it.
While I agree with MisterJerk that you don't need a ton of power to have fun in a car the stock 4A is just too damn slow IMO. I wouldn't recommend you triple the HP and try to use power to cover up lack of experience but I don't think that's going to happen with another 20-40 hp. I'm an AW11 guy but similar weight and stuff. I feel the 4A really starts to get fun in the 140-180 hp range.

If you want to run the 7A on the stock BT ECU you are going to want to get a wideband and monitor the AFRs. Since the BT is MAP it won't see the extra volume going into the motor so you will likely need to compensate somehow. An AFPR might be a good way to go. You could also try to find an injector about 12% bigger but you may still need to fine tune it from there.
You also need to hope these mods don't change the VE curve too much. If the whole map goes up or down you can compensate but if the curve changes then it means you might go too lean in one area and too rich in another.
If you have the money JE customs are a great option. I can get JE, CP and Wiseco pistons and believe they are all high quality and good options though I believe their high comp shelf pistons leave a bit to be desired. With the added compression from the long stroke though the low comp CP shelf piston may not be a horrible idea if they were compatible with the rotating assembly.

I have a number of rod options available on my website including the Crower's, Carrillo, and Tomei.
http://matrixgarage.com/store/bottom-end

I can get anything else from Crower as well including this stroker kit.
http://www.briancrower.com/makes/toyota ... oker.shtml
This is one that goes into the 4A block.
Personally I would keep the bore at 82mm to give you a little more wall thickness.

I may have a couple other options include stroking the 4A block which means you don't have to do all the extra work compensating for the taller deck. I think I can get you a 7A crank that will meet your needs but I think the rotating assembly would eat up a good portion of your budget. PM me if you want to discuss options and have me price them out.

[morningstarr86]

You guys are awesome. Thanks for all the info. I gonna run everything I found out past my mechanic (grandpop) and see what options are the best for us. Thanks again.

[NZ4age]

If you do go ahead with the 7age you could also try these guys, Barry specializes in 7age and 9age engine components http://www.mrpltd.co.nz/index.html