NG horsepower upgrades
David.Payne at brinksinc.com
David.Payne at brinksinc.com
Wed Aug 25 14:40:37 EDT 2004
I'm at 10 to 1 C.R. (stock) and can run 89 octane with no problem. With 87
I do notice a difference in power as the computer takes out timing. That's
why I thought I might be able to get away with 11 to 1. I know that some
D16 and D15 Hondas can get away with a little over 12 to 1 with 93 octane.
What car did the 5-3-1 exhaust come in? My stock system is right on 54mm
o.d. (2.125"). I put a 2.5" on a 3.0 conversion to a MB 190E and was
pretty happy with that so I figured the 2.3 would be fine with 2.25". I'll
rethink the 2.5". I'm OK with doing the exhaust myself. I'm curious about
the URQ intake tube, my boot from the fuel dist. to the tb is smooth on
inside.
Any one had experience with these heads?
What cat would you suggest?
Thanks, Dave.
|---------+---------------------------->
| | Alan Pritchard |
| | <apritchard at seaey|
| | e.com> |
| | Sent by: |
| | quattro-bounces at a|
| | udifans.com |
| | |
| | |
| | 08/25/04 10:42 AM|
| | |
|---------+---------------------------->
>------------------------------------------------------------------------------------------------------------------------------|
| |
| To: "Quattro List (E-mail)" <quattro at audifans.com> |
| cc: |
| Subject: RE: NG horsepower upgrades |
>------------------------------------------------------------------------------------------------------------------------------|
By the way, just checked custom autocraft, paul hasn't got the middle bit
listed yet, but I bought mine off him as a "second" it needed a tiny bit of
adjustment, but the quality for cost is superb....
http://homepage.internet.lu/customautocraft/main.htm
Best Regards,
Alan Pritchard
Network Administrator
Mechanical Design Engineer
Seaeye Marine Ltd.
+44 (0)1329 289000
-----Original Message-----
From: Alan Pritchard [mailto:apritchard at seaeye.com]
Sent: 25 August 2004 14:51
To: 'David.Payne at brinksinc.com'; quattro at audifans.com
Subject: RE: NG horsepower upgrades
Research suggest sticking with 35mm exhaust valves, and stock inlets,
possibly use 7mm stem exhaust valves instead of 8mm stemmed items, about
25-30 us dollars each, enlarging the inlet can lead to head cracking.
Searching around uk vw sites I decided to stick with 10.5-1 cr for safety,
and im thinking of 95-98 uk octane... and aftermarket efi and spark, also
ceramic coating... I think 11-1 on cis is too silly.... Ditch the stock
manifold and go for the 5-3-1 affair...worth ~5bhp on its own apparently,
and maybe more at the top end. Buy a custom autocraft cat back system for
~£200 iirc... off the top of my head, that's 2.5" don't try and make your
own (this is Quattro right?) it's a nitemare imho, also stock system is
2.25" anyway. The custom autocraft system made a very noticeable
difference,
but that was after a schrick 272 was in....
The stroked bottom end on a big valve head is reputed to make 170+ on its
own as far as I can tell from the internet, not sure if that included
cam...
Bin cis, it's the biggest restriction at the moment, plus the car idles
like
a biaatch cammed up... don't even know if mine will pass emissions at the
moment...If you are in the uk, chuck the cat away, maybe put another
silencer in its place, mine is going...
Do a bit of head and manifold cleaning up....
If you must stick with cis try and get a urq airflow meter-tb "tube" its
aluminium instead of waffled rubber, modify it to take some samco or the
like to your throttle body. Heard about this on the golfs, I think one guy
even made his own with copper tubing, apparently this makes a noticeable
difference in drivability...search the internet....
Personally, with your guidelines id do this....
Organize a 5-3-1 manifold and dp, fab up a silencer between the dp and
aftermarket exhaust system.... Stage 1..... expect ~10hp+ and a good
helping
of drivability.
Wait for my spare head ;) and big valve it with a 272 cam in it (don't
think
you could get away with a 276 on the road and cis).got to be a total of
160+
at this point, by feel anyway....
Then realise you need to take that cis crap off and put it in the bin, have
fully mappable ignition and fuel, possibly even with wb control.
Total cost...
Manifold+dp £50
Exhaust £200
Dp-exhaust section £50
Valves, machine work £150
Cam £300 new (ish, mine was about £200 second hand)
Aftermarket efi (megasquirt) ~£400
So around about £1000
Thatll get you 180-200 bhp imho
A turbo motor will cost less than that and give you 220BHP almost
instantly....
My reason for doing a NA upgrade is purely to prove a point ;) and try and
get some good times in a NA AWD drag class ;)
Best Regards,
Alan Pritchard
Network Administrator
Mechanical Design Engineer
Seaeye Marine Ltd.
+44 (0)1329 289000
-----Original Message-----
From: David.Payne at brinksinc.com [mailto:David.Payne at brinksinc.com]
Sent: 25 August 2004 14:28
To: quattro at audifans.com
Subject: NG horsepower upgrades
I'm looking for some logical paths to take to up the HP of an NG motor. I
want to keep the CIS (just spent a bit fixing it all), and want to maintain
as close to a stock appearance under the hood as possible. Some of the
questions I have are:
Is the 4KQ manifold and downpipe more efficient than what I have (1989
90Q)?
Is the NG head basically the same as an 8V hyd. GTI head plus a cylinder?
Dependent on the answer to the previous ?? what is the recommended valve
sizes (head and stem)?
How much compression can I get away with using 93 octane fuel?
What is the best cat to use?
My current plan is to use Blau's cam, enlarge the TB, fab up a 2.25 inch
cat-back exhaust, mill, port and big valve the head, shoot for about 10.5
or 11 to 1 compression. Desktop Dyno says that with 10.5 comp, 42mm intake
and 35mm exhaust (I guessed on the sizes) I should have 155 hp at 6000 and
162 lbs/ft at 4000. Using the same combo on the 2.6 bottom end takes you
to 161 hp and 173 lbs/ft. As good as the leak down numbers are on my
engine, I'll have a hard time justifying the 2.6 bottom end.
Alan Pritchard, lets compare ideas!
TIA,
Dave Payne
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