Show me some power

M

MarkB

Daily Driver
Now that I have everyones attention:D

Short of drastically altering the FI 1500 engine with cam replacements, piston changes etc; Are there ways of altering the X that would lead to improved performance for the average owner. eg. K&N marketing material states that by using one of their filter products, an increase in HP can be achieved. Is this the experience of X owners. If so, what is the increase?

Are their any other common modifications that would lead to a little more power on a small budget?
 
It's The Usual stuff.

* K&N could help.

*A good set of headers and exhaust does help.

*Making sure the engine is in good condition with proper state of stock tune, good spark plugs and etc. keeps it running well.

*Beyond this, cylinder head mods, cam, increase compression, different intake and etc. makes the real difference.
 
My solution is turbo.

I believe I'll have less than $300 into the turbo system when it is done. Though I do already have the turbo in the garage and I'm running megasquirt already.
 
As others have stated... there is also some FREE hp out there...

Relatively free... especially if you are replacing some parts on a maintenance basis...

1. All K&N's for the X really do WORK... as attested to by several folks (me too) on this site. I believe a 2710 fits the stock can... and there are several others listed for the FI units with or without the ELBOW.

2. The inlet snorkel on a stock carb Air Cleaner needs to be sawed off until there is a 2 1/2 inch opening... and then preferably snorkel it down into the Left air intake... and also remove the gridwork from BOTH inlet vents, allowing about 25% more air to flow.

3. On a stock FI unit using the stock can... use a conical K&N but then drill or punch several large holes around the perimeter for increased flow. Most eliminate the can altogether.

4. Bosch Platinum plugs, $1.99 each (WRX7DP, I think...) "free" if yur doing a tune up... and you can spend more for the duals or 4 electrode plugs, but I haven't seen/heard of them being much of an improvement over the single platinums.

5. Proper advance, proper WORKING advances be they vacuum or mechanical or both.

6. Ditto for the vacuum operated systems that are allowed to operate via the three-way thermo-valve. Insure the valve is working allowing the proper GULP function, vacuum advance and secondary on the carb to function... and if allowable in your area... rip it all out if it isn't. Use direct vacuum links.

7. Enhanced cooling via rain-tray removal... Argumentative... but works for me.

8. If allowable... installation of a "test-pipe" in place of the CAT. I'm about to complete a decade-long test and will soon post my results!

9. If an FI... insure injectors are cleaned and operating properly. Best to have them professionally analyzed and cleaned.

10. Update tires and experiment with pressure. Don't neglect the brakes and alignment either.

Do these things and you will have an X'ceptionally enjoyable ride for very few dollars spent. More details upon request... have fun!
 
That's the list I was looking for Tony. Thanks!

Tony,
Thanks for providing the list. As far as the K&N filter goes - what kind of performance increase do you think you achieved by using it?

As far as the Cat. Converter goes, if the internals of it were to be "altered" to allow straight through exhaust flow, would that have similar advantages to a straight test pipe?

Probably stupid questions, but I thought I'd ask them anyway.
 
A good list there Tony...

I would add one thing:

11. Lose weight on the car, i.e. clean out the trunks of extra crap. :)

Altering the CAT is a viable option, and would help performance, but a smooth-sided "test pipe" is a better performing solution. It will be louder sounding than an altered CAT pipe, which would provide some resonator effect.
 
A lightened flywheel makes a nice improvement as well. Easy to do if you add it as part of a clutch replacement job.
 
Tony's list

Black-Tooth said:
4. Bosch Platinum plugs, $1.99 each (WRX7DP, I think...) "free" if yur doing a tune up... and you can spend more for the duals or 4 electrode plugs, but I haven't seen/heard of them being much of an improvement over the single platinums.
***** I personally have experienced lots of driveability problems with these plugs. If a car comes in with them and the owner has ANY issues, out they come. **********

8. If allowable... installation of a "test-pipe" in place of the CAT. I'm about to complete a decade-long test and will soon post my results!
quote]
****** I agree 100%. My 1979 will accelerate in 5th gear with the test pipe in, with the cat in I must downshift at the same spot. And I get improved gas mileage with the test pipe!

Chris Obert
Click to expand...
 
budgetzagato said:
I would add one thing:

11. Lose weight on the car, i.e. clean out the trunks of extra crap. :)

Altering the CAT is a viable option, and would help performance, but a smooth-sided "test pipe" is a better performing solution. It will be louder sounding than an altered CAT pipe, which would provide some resonator effect.
Click to expand...

I know in a forced induction engine a good CAT (meaning not clogged) will flow better than a gutted CAT. I assume the same is true in a NA engine, though the difference felt is probably less.
 
Plugs

Chris, if you don't like the platinums, do you have a plug you can suggest?

Jim in Atlanta
 
I can suggest...

Bosch WR7DTC, it's a 3 side-electrode version of the Bosch Super Copper (resistor). Lots of sharp edges for good spark and the 3 electrodes mean the gap (set at factory) lasts a looong time. For those who wish to install-and-forget, at least for a few years.

The platinums don't do well in carbureted cars, or in cars that have points. Otherwise they do ok, except they can suffer a sort of high-speed glazing. One benefit is they warm up quickly and seem to help a rough/cold idle. Trade off is in high rev or high temps. I used to run them in my '75 Scirocco without issue, much to the mystification of my auto tech friend, but perhaps I was just lucky.

The WR7DTCs are what I've run in my Lancia Beta Zagato as well as currently in my Bertone. Solid and reliable. :cool:
 
Greg... just LOOSING WEIGHT does quite a bit...

Steve H mentioned this and I too have experienced the same... 30 pounds off the DRIVER makes for quicker steering and its that much LESS weight the car has to accelerate, turn or stop!

HA!

I'm working on this very same "performance enhancement" as we speak!
 
WOW... I forgot! AMEN to this!

... and the cost is relative cheap for the enhancement. Lots of fun too!

PBS no longer BALANCES but may still provide the milling. It WAS 65 bucks for milling and balancing and with shipping, cost about 90 bucks overall. I highly recommend it and in most cases, the flywheel looses about 4 pounds, be they 1300s or 1500s...

Really revs much quicker!
 
Hmmm... thanks for the endorsement...

The "test pipe" experience you've had matches mine identically...

As for the plugs... I've used Bosch Platinums in two X's over 10 years and never had a problem. I felt an IMMEDIATE improvement in power and MILEAGE over the conventional plugs I've tried... but have never used any other platinums.

Interesting...
 
Yur welcome...

Thanks for providing the list. As far as the K&N filter goes - what kind of performance increase do you think you achieved by using it?

You're welcome... Do consider the lightened flywheel when it comes time to change out the clutch... you'll love the difference.

I'm probably gonna get shot for this... but installing a K&N feels like an increase of about 3 hp. I mean... you really can FEEL the difference. Same goes for using the Bosch Plugs. But saying these two things would be an increase of 6 hp on a 75 hp engine sounds ridiculous... but... it does FEEL like it.

As far as the Cat. Converter goes, if the internals of it were to be "altered" to allow straight through exhaust flow, would that have similar advantages to a straight test pipe?

Yeah... but as Greg says... the pipe would be better, and less weight hanging off the back too. Mine was built with about 10 bucks in materials and that included HOT paint!

Probably stupid questions, but I thought I'd ask them anyway.[/quote]

NOT stupid... what's NOT smart is NOT asking about EVERYTHING on this forum FIRST. I've learned that one the HARD way. Someone here has done it faster, easier, and cheaper before... and its best to take advantage of that!
 
Mark...

Here's some PROOF about what I said about always asking questions here first.

Mark Plaia and Steve Hoelscher are probably some of the most knowledgable X owner/racers on this planet and... MARK ASKED... and this time, Steve answered...

SMART!

Here's the commentary and it answers your CAT question too!

I am curious about the difference in flow between:
1) Three bolt catalytic converter as used on carbureted cars
2) Four bolt catalytic converter as used on fuel injection cars
3) 1 3/4" cat "test pipe"

The early 3 bolt converters used the so-called fluidic bed approach utilizing a cage full of loose beads to provide exposure of the exhaust gasses to the catalyst material. The later 4 bolt converters use a honeycomb matrix to expose the exhaust gas. Since you can actually see through the 4 bolt type, I wonder if it does, in fact, provide a lot of exhaust restriction.

A 1 3/4 inch diameter pipe has a flow area of 2.41 square inch. I don't have a cat converter handy, but I remember them being about 4(?) inch X 7(?) inch. So, that would give a nominal flow area of about 28 square inches. Now if the honeycomb matrix is sitting in there (that you can see through) blocking say 50% of the flow area, that leaves a remaining 14 square inches or 580% more flow area than the straight pipe. Even if the matrix blocks 75% of the available flow area, that still leaves a 270% greater flow area.

Now, this is simplistic admittedly, because we are dealing with a dynamic situation. Bernoulli must be served, so there is a cost when the flow goes from a smaller area to a larger area and back down to a smaller area due to pressure changes. But, my fluid mechanics tell me that the reasonably long (and non-abrupt) taper at each end of the cat converter helps to mitigate the effect of the pressure changes.

The situation for the early style catalytic converter is different because of the approach. The idea with this style is like the old vacuum cleaner demonstrations where the outflow from the vac levitates a bunch of balls in a tube. The beads in the cat converter are liable for breakage, crumbling, clumping or otherwise getting in the way. And, never is a straight through flow path presented.

So, I speculate that the catalytic converter on a fuel injected X (NOT carbureted) presents very little restriction to flow, and it may not be worth changing out to a test pipe on a fuel injected car.

Prove me right or prove me wrong.

Ciao,
__________________
Mark Plaia
74 X1/9 - il mela verde
Has all the good stuff
​
Mark PlaiaView Public ProfileSend email to Mark PlaiaFind all posts by Mark PlaiaAdd Mark Plaia to Your Contacts
#2
post_old.gif
Today, 2:10 pm
Steve Hoelscher
user_offline.gif

Daily Driver
Join Date: Aug 2008
Location: Saint Augustine, Florida

I own one :)
I bought it at a garage sale. Really. As of right now its stored at a friends shop in Alabama.

Quote:
Originally Posted by Mark Plaia
I am curious about the difference in flow between:
1) Three bolt catalytic converter as used on carbureted cars
2) Four bolt catalytic converter as used on fuel injection cars
3) 1 3/4" cat "test pipe"
,

That's easy. And I don't need a flow bench to test it. The fluidic bead cats flow like crap. That's why most manufacturers went to the honeycomb matrix. The matix type flows way better than the beads. This is well known by the Showroom Stock SCCA racers that have to use the OE converters. Also, new converters flow better than used converters.

As for comparison with a test pipe. I haven't tested an FI X with/without a cat but I can tell you that a "test pipe" will flow better than the cat. Even if the matrix has a significantly larger area, even when considering bernoulli's priniciple, the exhaust pulses don't pass through the matrix as effectively. The converter acts much like a pulse dampener. As a result, the exhaust gases loose their velocity passing through the chamber and matrix. The loss of velocity means the loss of the scavenging effect.

Larger converters, while having more area for flow, cause a greater loss of velocity. So there is no free lunch.
__________________
Steve
1x5
​
Steve HoelscherView Public ProfileSend a private message to Steve HoelscherFind all posts by Steve HoelscherAdd Steve Hoelscher to Your Contacts

​

#3
post_old.gif
Today, 8:34 pm
Mark Plaia
user_offline.gif

74 X1/9 - il mela verde
Join Date: Aug 2008
Location: Springfield, OR

Thanks for the information...
I knew someone had been through the thought process.

Still, it would be cool to have dyno results from a four way test: Stock 4-1 manifold & head pipe versus header, with and without catalytic converter.

A flow bench would not show the effect pulsatile flow of the exhaust stream, so that would not be as good a measure.

The stock 4-1 manifold with head pipe would probably have the pulses a bit more homogenized than a header setup, and perhaps show a bit smaller difference between cat and straight pipe than would a header.

Ciao,
__________________
Mark Plaia
74 X1/9 - il mela verde
Has all the good stuff

​
 
Fiat Uno Turbo Mk1 unit - a straight forward engine swap.

Std 105 hp. Easy remaps to 150++ hp. Bolts to orig 1.5 gearbox but best use Uno internals. Cheap if used.

Ebay (UK or Germany) is your friend. EPA maybe not.
 
More HP?

Black-Tooth said:
I'm probably gonna get shot for this... but installing a K&N feels like an increase of about 3 hp. I mean... you really can FEEL the difference.
Click to expand...

I'm not doing any shooting (although I'm sure this'll be considered controversial) but a few years back, I recall someone in the FA community dyno'd an X (FI I believe) with a K&N vs a stock air cleaner with stock air filter. He saw no difference in HP. He did see about a 1 - 2 HP increase by removing the air filter entirely.

He figured the downside without the air filter is you might get about 10% less life out of the engine. But from what I understand, an X engine in good shape will go about 180,000 miles, so even if it were 20% less miles, that's still 150,000 miles. For me at least, that's more than 15 years of fun driving. (During the rainy season, I put the air filter element back in.)

Larry
'79 X
'86 X
'81 Spider 2000
 
Just curious...

Did he say if there were any changes in the power or torque graphs? Like HP staying up longer or anything like that?

David.
 
I honestly don't recall. This was a few years ago. If I can find the old email, I'll repost (but that's on another computer with a flaky hard drive).

Larry
 
You must log in or register to reply here.
Back
Top