914 1.7 ....getting more HP???

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Switchblade
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914 1.7 ....getting more HP???

Post by Switchblade » Wed Jan 23, 2002 4:38 pm

Now that I know I have the "syndrome" and that I must tear my engine down. What better time to make it better.

How can I make this engine more powerful but stay in the 1.7 displacement range??? Is it possible? What are the trade offs? Cost?

Then engine comes out this Saturday!! Image

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Racer Chris
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914 1.7 ....getting more HP???

Post by Racer Chris » Wed Jan 23, 2002 9:41 pm

Go for it Switchblade!

How much power you can get will depend on how big your budget is. Bigger valves and flow work with a bigger cam will do most of it. See my last post under Racing Story about using 1.8 heads on a 1.7 engine. The 1.8 heads are easier to get in modified form. Choose the cam carefully for the level of head work and expected rpm range. If you are sticking with FI don't get too crazy. My all out race motor makes nearly double the factory output but only above the stock redline. Stock springs will cause valve float above 6200rpm.
Chris

ray greenwood
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914 1.7 ....getting more HP???

Post by ray greenwood » Thu Jan 24, 2002 7:07 pm

100+ Hp with the basically stock 1.7 is not that hard even without displacement changes. But also without displacement changes, its about the limit. Compression on stock FI 411/412 was 8.2:1 with the small domed pistons. That netted 82 hp from the factory. A web cam, bigger better valves and a decent port job WITH tuned out stock injection and a slightly better exhaust and a basic electronic ignition netted me 102 at 4200 rpm. If you are upping the displacement and staying in the stock parts realm...Chris is exactly right. The 1.8's are easy to come by and a good starting place, otherwise IMHO the combustion chamber shape in the 1.7 is much better than the 1.8, has better quench area and responds to decent porting better than the 1.8...partly because it has a little more metal to work with...so don't get rid of them eiher way. Ray

Switchblade
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914 1.7 ....getting more HP???

Post by Switchblade » Mon Feb 04, 2002 6:29 pm

I don't want to change the displacement. And the suggestions so far are great...But...

Can anyone give me some more specifics on types of Cam's (manufacturers, part #, etc), size of valves(will they work in the stock heads), stock fuel injection modifications(how to, or who/where to)...

Thanks in advance!!

Jeff

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Bleyseng
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914 1.7 ....getting more HP???

Post by Bleyseng » Mon Feb 04, 2002 9:22 pm

Jeff,
I think the largest valves would be 42x36 same as the 2.0L 914 ones. I hear the Web cam 73 works fine with the stock FI (get a cam and lifters). Have the heads ported and polished by a pro ($$$). It's worth the money and not a do-it-yourself project.
Ray Greenwood posted lots of info on the mods to make on the FI system.(do a search)
I think the first thing is to get a good distributor. Then blueprint it so it works prefect. Or buy a new one as most of them are 30 years old. The distributor controls both spark and injection timing.
Put on the larger SSI heat exchangers with a Bursch.
Put on the larger 50mm throttle body off a bus.
Ditch the oil bath air cleaner for the paper filter one and use a K&N filter.
Balance the moving parts of the engine. This is free HP! This means the crank,rods, pistons, fan, flywheel, pressure plate, clutch. Again take them all to a shop that does it, costs about $150.
After it's running take the car to a dyno shop that can tune the FI, mainly the MPS. You want the fuel mix to be right at part throttle and at full throttle so you don't go lean.
Have the injectors cleaned or rebuilt so you get a good fuel spray pattern.
I am sure others will chime in with more...
Geoff

------------------
76 914 2.0L

ray greenwood
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914 1.7 ....getting more HP???

Post by ray greenwood » Tue Feb 05, 2002 10:12 am

Hello, I think Bleyseng is right on. Before you make changes to the FI (there are a lot that can be done)...straighten out the mechanicals first. Compression up to about 8.5:1 give or take helps the FI (and any motor) alot. I use 42x38 valves. Probably a mm or 2 too large on the exhaust, but it runs great. The web cam is a definate. The distributor...either rebush...or get an new one. Several of us are working on mall bearings for the stock dist. Its on the shelf for the month until I get my tranny done. This engine needs a lot of ignition. Balance everything. The bus TB is an excellent size. I use it. After the mechanicals are correct, you can start on the injection. That way, any variables/variations you can see will just be fuel system variations. With proper tuning, 100 HP is not that difficult. Ray

ErnieDV
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914 1.7 ....getting more HP???

Post by ErnieDV » Thu Feb 07, 2002 3:41 pm

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Bleyseng:
Put on the larger 50mm throttle body off a bus.<HR></BLOCKQUOTE>

Perhaps I missed something earlier - is this 1.7L a D-Jet or L-Jet system? AFAIK all Bus FI were L-Jet so I wouldn't expect that you could use a Bus throttle body on a D-Jet 1.7L.

ray greenwood
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914 1.7 ....getting more HP???

Post by ray greenwood » Thu Feb 07, 2002 6:27 pm

Yes, I use an l-jet TB on D-jet. They use the same mount and gasket. I had to use a tailpipe expander to make the inlet match the TB. The TB is just a TB. The injection parts are slaved onto it. Some models do not use the throttle valve switch...so they do not have the holes tapped, but the casting mount for the switch is there and just needs to be tapped. The non throttle valve switch version uses a short throttle shaft. The hole in the bottom has a small freeze plug in it. You can swap plates and shafts in minutes. The little shaft seal at the top will pose a problem because it is an odd size. They make a standard seal one mm smaller in OD. Just buy that one and epoxy it in. The differences in L-jet and D jet were in the electronics and wiring, not really too much difference in the air plumbing. Ray

stevestromberg
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914 1.7 ....getting more HP???

Post by stevestromberg » Thu Feb 07, 2002 7:54 pm

i built a 1.7 for a 70 914 I upped the Comp. to 8.7, thur in a Norris 284x cam. Balanced it,Put a set of 36 Dels on 1.7 Heater boxes with a Bursch header and muffler. That car would wind up nicely. We ran I agaist a Stock 73 2.0 FI and the 1.7 was quicker from 35 to 75 in third gear. I like short stroke motors.Steve

[This message has been edited by stevestromberg (edited 02-07-2002).]

ray greenwood
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914 1.7 ....getting more HP???

Post by ray greenwood » Fri Feb 08, 2002 3:44 pm

The 1.7, in stock form...and I mean stock pistons and heads, responds better than the 2.0 and the 1.9 to good things like cam changes and better valves. The combustion chamber shape of the head, with its quench matching the small domes of the stock FI piston works very well . just an addition of a good cam and larger valves makes a huge difference in response, compared to the same mods on the 1.8 and 2.0....IMHO...Ray

Switchblade
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914 1.7 ....getting more HP???

Post by Switchblade » Mon Feb 11, 2002 12:58 pm

Gentlemen, thank you for all the great help and ideas!!

I now have the engine out and almost completely disassembled. Here are some interesting items I have found(please comment):

The is an air control "thingy" that looks like it adjust air across the heads and the oil cooler (two flappers one on each side that are apposed - only one open at a time) but they have nothing connected to the main bar that connects them together???

Fan is missing 5 fins all in the same 1/4 radius of the fan(vibration?), anyone know where I can get one of these cheap??

Dead Mouse and dogfood in heat exchanger flapper housing!!!;P

Small mystery pulley on the drivers side of the case(lower middle). By appearance it hasn't had anything riding in it for a "LONG" time???

I anxiously await your comments...

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Dave_Darling
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914 1.7 ....getting more HP???

Post by Dave_Darling » Mon Feb 11, 2002 1:20 pm

Cooling flaps. Good, necessary--keep them. The pulley is related--note that there is a hole in the engine tin up above the pulley, and a small lever on the cross-shaft for the flaps above the hole. The thermostat (a small accordion thing) mounts to a bracket on the side of the sump, and a cable goes from it to the pulley, around the pulley and up to the cross-shaft of the flaps. When the thermostat is cold, it pulls the flaps closed, when the thermostat is warm it expands and the spring on the flaps pulls them open.

Missing fan blades == bad. Get yourself a used one, just about any Type IV used-parts place should be able to get them. I think Pelican can get them new, but used will be a lot more economical. Just make sure there aren't any blades missing before you buy, and once you get the fan make sure to transfer the timing marks (if you use the ones on the fan) to the new fan.

--DD

------------------
1974 VW-Porsche 914 2.0 (Type IV powered!)

Pelican Parts' 914 Tech Geek http://www.pelicanparts.com

Switchblade
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914 1.7 ....getting more HP???

Post by Switchblade » Mon Feb 11, 2002 4:02 pm

Thanks for the Thermostat info Dave! That all makes sense. I have had the car now for 8 years and that has never been there and I never noticed any issues. I will find the needed extra parts and put them on though.

Thanks again! Image

Switchblade
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914 1.7 ....getting more HP???

Post by Switchblade » Mon Feb 11, 2002 4:08 pm

This whole process was started with me finding out that my oil leak, "the syndrome", stems from a case bolt that has come loose.

I was told that this case bolt also hold up another part??? This doesn't appear to be correct in my engine. It is just a case bolt... Image

any comments?

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Dave_Darling
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914 1.7 ....getting more HP???

Post by Dave_Darling » Mon Feb 11, 2002 4:56 pm

The case bolt is in the right-hand side of the case, between the pushrod tubes. It holds up the oil pickup tube, which in turn holds the sump plate.

--DD

------------------
1974 VW-Porsche 914 2.0 (Type IV powered!)

Pelican Parts' 914 Tech Geek http://www.pelicanparts.com

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