[SV3Power]

don't forget, though someone may have mentioned this already I'll throw it in-
7afe- low-end torque, low redline, weak components, long stroke
20v- high revving, high end power, crazy redline, high compression

running a 20v 7age and expecting 20v+7a performance seems crazy. The internals probably won't be able to take 20v-esque rotational speeds or compression, and the 20v head probably won't do much to help low end torque, which is the 7a's forte

Can we please, please put this to rest? So much of what people post about the 7AGE is just what they've read, posted by others who are also just repeating what they have read. It is mostly theory and guesswork, mostly offered by people with no exposure to or experience with anything resembling a 7AG. Sliverstorm, I'm not suggesting you haven't done your homework, but some of your points are oversimplified and frequently misused all over the internet.

The 7AFE is by no means a "torque monster". There's just no point to revving a stock 7AFE. Naturally it has a lower redline, which is due primarily to the fact that every component and system on a 7AFE is optimized for power and efficiency at reasonable RPM, not because the internals are too fragile to withstand power.7AFE bottom ends are not made out of graham cracker crumbs. Mine happily holds 7500 RPM indefinately with stock rods and crank, new rod bolts and decent machine work. Compression ratios in excess of 11:1 are not a problem.

The increased displacement of a 7AG hybrid will move more air for any given engine speed, and therefore take advantage of the 20V cylinder head and camshaft capabilities at lower RPM than would be necessary for a 4AG with the same head and cams. Anyone who took the time to properly build a 20V 7AGE would almost certainly get all the inherent goodness of a 20V, but with a broader, meatier powerband at generally lower engine speeds. You end up making compromises, naturally, but the end result should be a very good thing.

 

[filonin_2]

Owned, again.

 

[sliverstorm]

Never said it was a torque monster. But by your own documentation on the build, you got 140ft-lbs out of it, which is something like 1.4x what a 4age has, which is my reference point.
and I figured longer stroke would have an effect on higher rpm. maybe I'm wrong though, and stroke length doesn't matter?

and really, while the 7age/fe may not be super torquey, compared to other NAs that we put in mr2's- 20v, 4age, 2zzge- it seems the one place it comes out on top is torque, so that is how I think of it. 20v especially!

 

[SV3Power]

Well...the torque my engine makes is partly due to increased displacement (not the longer stroke per se, but the displacement it creates), partly (substantially) due to increased compression, and of course partly due to better cylinder filling with different camshafts.

One of the points I was trying to make was that the stock 7AFE is no torque monster. I wasn't trying to suggest that a 7AGE wouldn't make good torque. A correctly modified 7AFE would also see an increase in torque.

The stroke does have a fairly direct effect on RPM potential, as it directly impacts mean piston speed at any given RPM. Piston speed is a fairly useful guide to maximum engine speed. In my engine spinning 7700 RPM with an 85.5mm stroke, the mean (average) piston speed is 4320 feet per minute. A 4AG with a 77mm stroke can spin 8550 RPM to achieve that same piston speed.

 

[Vishal25pm]

how much boost should a stock blacktop 20v ecu take?

 

[DrWonderEyes]

alot if u take away the igniton timing and make it super rich!. but seriously. making an intake manifold for that thing is alot of work in of itself. i dont think u could get 4psi in the stock intake manifold cover that goes over the ITB's

 

[Vishal25pm]

well i was thinking for getting one of these..

http://cgi.ebay.com/ebaymotors/20-V...QcmdZViewItemQQcategoryZ36474QQihZ004QQitemZ140204638623QQrdZ1QQsspagenameZWDVW


so that takes care of the manifold.

 

[DrWonderEyes]

there u go lol i've seen that before. thats basically what u need. to start turboing a twenty valve 4age

 

[Vishal25pm]

well, i dont want to turbo it, i would like to put a sc12 on it and keep the stock pulley i think depending on how much boost the ecu can hold.. so please anyone???

 

[fastrax203]

I don't mean to beat a dead horse, but would these rods help with the lack of the 7As ability to rev?

http://www.belfabracing.com/product_info.php?cPath=263_225_355&products_id=1314

With these and some high comp 16v pistons on the 20v head wouldn't that enable the 7A to rev to the 8k redline that the 1.6 20v revs to?

 

[filonin_2]

It would be a bit safer but you still wouldn't be making more power up there and there still wouldn't be a point to revving that high. If I had the money though, I would so buy those rods. But I already have like $1400 in my 7agze build, so I really can't be spending more.

 

[fastrax203]

im not one to care much about revving if there's no power up top. i would use some bigger cams with more lift to make the high rev-ability more useful. the main advantage this engine would have over say...a 20v is the low-midrange punch and low rev drivability that the 20v lacks, somewhat lackluster in the lower rev range.

 

[F0Bman]

That thing sounds like it could be a real monster.