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horsepower increase?


CEAZERKHAN

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The A14 is around 70 hp? on a good day? If you are used to driving EFI V6s or 150 hp four cylinders an A14 will feel slow.

 

would start by making sure your A14 is giving everything. Check the valve lash, ignition timing, is the secondary opening? maybe a compression check... if below 130 or one cylinder is low maybe rebuild before wasting any more time on this. Is the exhaust pipe crushed? I had a '76 and it wouldn't climb hills. The fuel filter was plugged. There are any amount of reasons for sluggishness that need to be explored and discounted before adding any performance increases..

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The A14 is a great motor with lots of potential.

 

The first thing I would do is get a DGV or even a pair of SUs. The stock intake manifold isn't great, because of the tiny plenum, but if you can TIG weld and have some machining skills, it's not hard to double the size of the plenum by welding in a part of a DGV conversion manifold from a 240Z.

 

One very quick mod is the distributor. You can re-curve it and maximize your timing advance to gain a couple HP and snappier response.

 

A good exhaust system with an early A12 exhaust manifold (from a 1200 I think) will give you a few more HP. Good headers are out there, but stay away from cheap headers.

 

You could always regear the diff too.

 

Other than that, everything else is internal engine stuff. I used to build these with 160hp for SCCA GT5 and DSR racers. They revved to 10K+ and needed rebuilding after two or three races.

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If welding, how about motorcycle carburetors on a custom intake? Each runner can be tuned for length. On a relatively stock or mild engine that won't be seeing over 6K, usually longer to pick up bottom/mid range torque.

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If for no other reason than the sound!!!!

 

Get slide carburetors, they work much like SUs and are constant velocity. No need for accelerator pumps because it's impossible to bog them off the line or at any speed. Response is instant and smooth. Carb is as large as needed and self adjusts for load. Also being basically side drafts, air flows almost in a perfectly straight line from filter to intake valve. On my L20B if I hold the throttle and the slide open I can see the intake valve. No going past a 90 degree bend on a down draft and splitting and dividing runners. Each cylinder has a massive 1.5" runner totally separate from all the others. I ran 4" air horns (no filters) and the total 'tuned length' was around 18". Later I had to shorten them to perhaps 2" to fit a 280z air filter. Even without the filter it felt different with the shorter ones. 

 

Very roughly 18" tunes for 3,000 RPM peak torque.

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Have to agree. With the enrichment on it cranks and cranks eventually fires. Once, twice.... 3 then 4 in a row speeding up the starter till you can let the key off. I like how it fires up (eventually) dead cold, and idles at 450 smooth as can be.

 

To speed this up I take the air filter top off and squirt gas in each hole. That fires right away but rough to try driving till it's warmed a bit. By the time the air filter is on and hood closed you're good. Once run, it restarts all day. What I need is an electric pump with a fuel rail to each intake runner with an orifice in each.... and a push button. Hot re-start is half a turn bump, throttle response off idle is superb compared to downdrafts that have quirky (though usually mild) lean/rich, flat spots, stutter, bog and secondary tip in. Not to mention you can flood a downdraft. For all the negative (cold start really) I find the positives, more power, much improved throttle response, drive ability and re-start far outweigh this. Oh! The sound!!!! The sound alone is worth it!     

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So as the resident A-series guy I'll chime in:

 

For bolt on parts; Weber 32/36 DGV down draft carb, header and a larger diameter exhaust. This will net you about 8-10hp. If you score some deals on parts it may be possible to do this for $250-$300.

 

For another $300-$400: reground cam Delta Cams 278 grind, dual valve springs (Iskederian still has them), thinner GX head gasket (raises compression) and clean up the ports (especially around the valve seat) I port my heads using a dremel.  That will net you another 10-15hp. This naturally requires taking the motor apart so if you can't do this yourself then it's not cheap.

 

So for $700 or so you can get maybe as much as 25hp more. Plan

on 18-20. It doesn't sound like much but you will notice a big difference....... It will still be slow relative to modern cars but it will Rev like mad.

 

The A15 in my 1200 race coupe makes 99hp at the wheels. I have a ported GX head, Delta Cam, Isky valve springs, 77mm bore, 11-1 compression, header w/2" exhaust and 39mm Keihin flat slide carbs. Other than the machine work I did everything myself. It cost me right on $2000 to put that motor together. 

 

 

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