D-Jet FI 1.7 improvements ?, What works performance-wise ? Options

[wheelo]

Hi - there,

does anyone have any wisdom on how to increase
performance on FI 1.7 motor?
I currently run with a Bursch Exhaust, but all else,
is stock...

thanks for any help ...

cheers... (IMG:style_emoticons/default/beerchug.gif)

Wheelo

[ChrisReale]

All I can think of is 2.0 heat exchangers and muffler, and I dont think it will help that much...?

[Bleyseng]

head work is needed -ie larger valves like the 2.0l heads-42x36 with some port work.
Maybe even more compression to 9to1.
A header instead of the HE's will help too.
I have got you to maybe 90hp doing all this, so about 10hp.
What else, maybe going to larger pistons will help.

Actually, if you really tune the engine with updated parts the little 1.7l is quite a good motor.
Geoff

[SirAndy]

does anyone have any wisdom on how to increase
performance on FI 1.7 motor?

the type 4 is weak on the exhaust side, so anything that will make it flow better helps.
a set of nice headers and you already got the bursch, which is a good choice.
get rid of all the smog crap.
set the vales to 0.004 when cold.
make sure everything is in good working order, all grounds are OK, no brittle cable, FI trigger points are good etc etc etc.
make sure it can breath a lot of cool air (like, no rain tray during the summer). check timing.

the max. HP of those little suckers is @ 4800 rpm, so don't be
surprised you don't get much pull @ 2000, keep the rev's up!

loose weight (you and your car (IMG:style_emoticons/default/smile.gif) )


i have a 1.8L with D-Jet and i tell you, they CAN be quick (IMG:style_emoticons/default/laugh.gif)
Andy

[nebreitling]

here a sketchy D-jet mod: add a pot inline with the CHT and FI harness. run it to the cabin. adding resistance will richen the mixture up. turning it all the way to the left will keep it stock. a slightly richer mix might get you a couple hp. more might foul your plugs or f-up your engine, so be careful.

better yet, just make sure that your FI is in TOP shape (i should take my own advice on this).

[wheelo]

Sir Andy.... your the man !

I have been going through my car cleaning and restoring like mad... trigger pts are good, she is a strong runner, just a tad slow with the throttle resp.
But you are right about the RPM and FI ... smooth !
Smog junk being all the rebreather crap ?
Is there a aftermarket air cleaner assembly that would allow me to dump the stock one?
Then I could plug hoses. I think that's great ...
just what the motor needs, less restriction.

viel danke (IMG:style_emoticons/default/smilie_flagge6.gif)

wheelo

[Bleyseng]

The hoses are good as they take and lessen the air build up inside the block. Plugged those hoses off just makes the engine case have pressure inside which then blows out the o rings and valve covers gaskets.
Disconnect the hoses to the charcoal filters if you want something to do.
A 73 1.7 already has the good air filter setup so you could add a k&n air filter.
Careful engine tuning the the key to extra hp with these engines.
If you want it to run 10% richer just unplug the air temp sensor.

Geoff

[lagunero]

K&N filter for a 73 1.7? I can't find one, at least not specific for the 1.7. They're for 2.0 or 1.8. If some runs these, please let me know the #. Thanks, alberto

[John]

You could always try an engine swap. That would boost the performance of that 1.7. 6-cyl Porsche engines all would have more power and would give you nice snappy acceleration. Of course, there are those here who have gone the Detroit method of increasing the performance.

You could also add a turbo to the 4-cyl. I saw one in Aurora Illinois back when I lived there. It was fast while it ran.

You could try NO2. That might help for a while.

Seriously, I have debated hot-rodding 4-cyls as opposed to going the 911 engine route many many times and I am convinced that you can spend much more money trying to make a lot of power with a 4-cyl than you would by simply swapping the 4 out for a 6. The six would run better, longer and would not need to be much more than stock. Besides, since the 914 is lighter than the 911, the engine will see even less stress and would last that much longer in the 914.

If you like the 4-cyl, then leave it as stock as you can. They run for a long time if done right and they seem to run well when maintained (at least in stock form with the fuel injection).

just my $0.02

[John]

or is that N2O? oh well, I meant nitros oxide......

[Dave_Darling]

Trick #1--get the car into good stock working condition. Like Aaahndy said.

Trick #2--get a real header, not the Bursch collector and muffler. Something like the Kerry Hunter, European Racing, or Tangerine Racing headers. They ain't cheap. You'll need a lot of muffler for them to make them streetable, too. The best of the lot would be the Tangerine Racing Super Header with the Phase 9 exhaust and "quiet can".

You may need to tweak the fuel pressure or tweak the other possible adjustments on the injection after you install the header. A dyno with wideband O2 would be the best way to find out what you need to do.

--DD

[weird_looking_cactus]

Im wondering how you would go about putting a turbo on it is there a guide somewere I can read up on this.

[Dave_Darling]

OK, people, say it with me...

"Everybody knows you can't turbo a 914!" (IMG:style_emoticons/default/lol2.gif)

No guide, no kit, you gotta do it all yourself. Learn to love welding, learn to love research and reading the Corky Bell book "Turbomania", and maybe get a couple of extra engines just in case you blow yours up...

There are pics of a couple of turbo setups around, but none that I know of where the turbo has run off of D-jet. (Did Jeff Shyu ever take pics of his D-jet turbo setup?? Aaron?)

--DD

[John]

Dave,

and maybe get a couple of extra engines just in case you blow yours up...

Yup, a 914-4 turbo will most likely blow up. The only turbo 914-4 I saw first hand blew up many many times. The car as I remember it looked kind of like a 959. It had that kit on it. It wasn't done that well and it was in the Aurora Illinois area back in 1989-1993 (when I lived there).

I am sorry, I don't have any pics.

The best way to increase power of your 1.7 and keeping the engine would be to do as everyone says and make sure the fuel injection is working correctly and get a better exhaust system (not just muffler). I used to have a header system for a 2.0 that had short tubes that bolted up to the heads and the rest of the headers bolted up to those flanges. That header system ended in a phase 9 muffler and it was reasonable to drive (no earplugs required). It was very strange looking, but it did seem to have equal length tubes for all cylinders.

[John]

Now that you mention it:

"Everybody knows you can't turbo a 914!"

I am half considering putting a twin turbo 6-cyl in the race car tub that is currently in my shop. That car is still on the roticorie and we have not decided on the engine. It could be built into a competitive club racer (not my first choice), or a real fun DE car.

Decisions, decisions...

[wheelo]

Thanks Everyone for their input !

good discussion/suggestions, I will look for a "true"
header. Keep her tuned and consider the upgrade to larger valve heads. (IMG:style_emoticons/default/driving.gif)

See Ya.... (IMG:style_emoticons/default/wavey.gif)

Wheelo

[Gint]

Hey, Welcome to the board wheelo! Post some pics of your 914 in the Members 914 pictures thread