Super Haidukken FireFlame MPG build

[K2e2vin]

I remember Mike(Calesta) was talking about using a turbo for better fuel economy. Ever tried it?

My brother's D15B8 took a crap(blown rings) and I'm thinking about rebuilding it for him. With that D15B8, he was getting roughly 52/40 mpg. Anyways, any comments or suggestions on the build?

Here is the plan:
D15B8 short block
PG6 pistons
P07(D15Z1 VTEC-E head) and intake manifold
TL1000R Injectors(4-hole 220cc)
Mercury XR2 turbo(too big?)
CX transmission with maybe 96-00 DX final drive
Converted P05 with Crome

I should note that the compression is VERY high with the setup(12.71CR). Hopefully the squish combined with the pistons would help control detonation. This car will probably have to run off of 89 or 93, but I don't mind.

Also, what about the injector position? Since the D15Z1 is a swirl type head, would it make sense to have the injector firing into one side of the port vs. both? I'm going for a lean-burn method here.

And the turbo; I'm aiming for low levels of boost during part-throttle driving(0 psi/no vacuum), and a max boost limit of ~3-5psi. Combined with that compression...can the pistons take it? Then there's backpressure due to gasses building up to turn the turbine...would a "turbo bypass" that goes from the exhaust manifold to the dump pipe work?

 

[Matts96HB]

I have no idea on the bypass. But everything else seems like its going to hinge on the tune. The tune is usually the true deciding factor with high comp builds..

 

[phunky.buddha]

I wouldn't go with compression that high. With super high compression naturally aspirated engines, you generally have to spend quite a bit of gas on them to keep them happy. With an n/a engine, you have to feed it fuel ALL the time to keep things smooth. With a boosted engine, you just feed it when your foot's deep in it.

I would recommend running a compression that's not too too high, then use a very small turbocharger. I don't know how the Mercury turbo performs, but you would ideally want something that starts to spool almost right off idle. The earlier your boost starts to come on the better- until you get a turbo so small that you're choking off your exhaust flow.

 

[K2e2vin]

Well the high compression is really an attempt at taking advantage of the lean-burn technique since the head is a swirl type design. Also, I was thinking that due to the small bore and the quench of the Z1 head, detonation shouldn't be as much of an issue than running similar specs on a larger bore engine.

btw, Bisi had no problems with a 13.3:1 compression street setup(D16A6). The huge compression increase on this setup comes mainly from the head. The piston itself has a 1.5cc dome(maybe a flat-top PM3 piston would be better?)

I guess the Mercury turbo is too big for my application; it looks like it was designed for a 1.6l. :/

 

[K2e2vin]

edit: NVM, PM3 pistons have a taller compression height so the compression actually went up.

 

[efhondakid]

My friend has a turbo from the turbo Ford Probe,(we're going to put it on his DPFI D15 and see how long it will last with no tune, no intercooler and waste gate blocked) I think thats what he said it was from, anyways its really small and would be good for what you want to do, quick spool and low boost.

 

[phunky.buddha]

Well the high compression is really an attempt at taking advantage of the lean-burn technique since the head is a swirl type design. Also, I was thinking that due to the small bore and the quench of the Z1 head, detonation shouldn't be as much of an issue than running similar specs on a larger bore engine.

btw, Bisi had no problems with a 13.3:1 compression street setup(D16A6). The huge compression increase on this setup comes mainly from the head. The piston itself has a 1.5cc dome(maybe a flat-top PM3 piston would be better?)

I guess the Mercury turbo is too big for my application; it looks like it was designed for a 1.6l. :/

I guess you could try the high compression lean burn stuff. Maybe try a vapor fuel system?

Bisi wasn't trying to maximize fuel economy.

If the Mercury turbo was sized for a 1.6, it might just be the right size for what you want to do. Go match it up on its compressor map.