EighTT

<center><img src="http://www.sae.org/automag/newenginereview/images/audi1.jpg"></center><p>Maybe I am misquoting you. If I'm not, I don't buy this. Not saying that you couldn't be correct, but I have serious doubts about this.

Here's a quote from the SAE article:

"The higher-output 165-kW (225-hp) engine uses a high compression ratio (8.9:1) for a turbocharged unit. The 1.8-L engine was extensively modified to attain the higher output reliably. The pistons, connecting rods, and big-end bearings were uprated to accommodate the higher combustion pressures. The double-mass flywheel and clutch were modified to match the greater performance. The intake manifold, turbocharger, and exhaust manifold are new.

A Type K04 turbocharger forces air into the combustion chamber via two charge-air intercoolers. Compared to the less powerful 132-kW unit, a modified airflow path, together with a larger air cleaner, ensures that the air reaching the engine has a temperature only about 30ĄC higher than ambient. This 80% charge-air intercooler efficiency keeps the engine supplied with an optimum flow of oxygen-rich air. Maximum boost pressure at the intake manifold can reach 200 kPa (29 lb/in2)."

A link to the article is below:<p><img src="http://home.san.rr.com/winefinds/1.jpg" border="0">

<B>Brad Willis</B>

<FONT COLOR="#FF6600">Mk 1.5 225q TT Roadster
H&R Coilovers
No Garrett
No Stickers</FONT>

<A HREF="http://home.san.rr.com/winefinds">SoCal Audi TT Club<ul><li><a href="http://www.sae.org/automag/newenginereview/audi.htm">SAE new engine review.</a></li></ul>

MichaelTT

I have read many tech descripts on the 180 vs 225 and all have said that the difference in engines are far more than you described...including the head is modified. Maybe an area for us to explore more??<p><img SRC="http://pictureposter.audiworld.com/AudiWorldPics/2000/tttiny.JPG" BORDER=0>

2001 Amulet Red 225TTQC
AMULETT

VAP

I've set out to learn the REAL differences between the "ACT" (180) and the "AMU" (225) engine codes. Scouring for the "actual" differences beteween the two engines. I dont know about clutch/flywheel or anything "back" of the rear oil seal. But I do know my search has turned up some very interesting facts. Not opinions mind you but cold, hard empirical facts. I didnt do this to belittle or take away from the 225 engine, its strengths or somehow make it the child of a lesser God. But I needed to know.

In my search I have found as far as cylinder head goes, its the same "core" unit part number. Also for a complete "head assembly." Which includes cams, springs, retainers, cam towers, cam followers (rockers), valves, valve guides, valve retainers, valve retainer keepers and valve stem oil seals. They're the same part number guys. I'm sorry if this bursts anyones bubble. Like I said, its not my intent to shatter dreams but merely to know the truth as it will affect the block/head assembly I purchase for my long term engine-building plans.

As far as the block goes there is the difference of pistons and its resultant loss of compression in the 225 engine; 8.9:1 in the 225 and 9.5:1 in the 180. The 180 wins that race hands-down by virtue of flat-top cast pistons whereas the 225 uses a cast, scalloped (dished) top piston, to lower its compression. Connecting rods are the same part number again tho there was a "superceded" part number in November of 99. Could be that all TT's regardless of HP ratings now use the same rods and early ones were perhaps different or maybe even weaker. Wristpins are same part number. Main bearings again, same part number.

Now I dont know about technical bulletins anyone has read or where all this info has come from. I tend to think its been speculation and marketing hype. Even the SEMA article Brad linked to was vaggue and ambiguous as to the actual internal differences yet very specific on the ancillary or bolt-on goodies.

No one has to buy into this. You may certainly think your motor is stronger. But I wont build an engine based on your beliefs. I have to satisfy a rigid set of parameters to tear into this project. Now I know I can do it with either engine but the sad truth is given what I now know to be true, the box-stock ATC 180 block/head, due solely to less $ will be my platform of choice.

All I know is if it uses 180 part numbers its a 180 "root" part. If the heads the same, the connecting rods, the main bearings, valves etc are all the same, then please, just point me in the direction to where all this hidden bolstering/reinforcing/strengthening/meatier/beefier parts are. Hell I'm easy to convince... for you see, I really WANT to believe. With what I want to do I NEED some of that touted over-engineering. But other than bolt-on stuff I'm being met head-on with what I've already got in place a 180 tall block.

And anyone may disagree. But first consider I'm not arguing or trying to sway you. I'm merely relaying the facts as I know them. Disagree all you want or need. But if you're going to win me over do it with substantiated truth and facts. I WANT to lose this disagreement... I really really do. But just "saying so" dont feed the bulldog. Show me!

Larrytt

hmmm, then the ONLY differences then are the intake, exhaust downpipe and intercooler plumbing? Basically that is it? Then the 225 could really be called a "chipped" 180? lol

Mance, with the flat top pistons then the 180 has a greater potential for more hp because of the compression?

Just Plain Cliff

Ain't that ironic, Larry?

Larrytt

which part? I find ALL of it ironic! lol

MichaelTT

<p><img SRC="http://pictureposter.audiworld.com/AudiWorldPics/2000/tttiny.JPG" BORDER=0>

2001 Amulet Red 225TTQC
AMULETT

avangogh

chipped? well differences in intake, exhaust downpipe and intercooler (dual) plumbing is big to me. After you make those changes to a 180 car, which includes time and money, how much effort has been spent? I'd like to see the 180 quattro mod verse a 225 stock quattro... this should prove to be interesting. I love all TTs but I think I spent my money well. And I am in process of getting my first mod, a MTM 255 chip, that should make an already fast car, faster! I'm sure a lot of 180 quattro modified cars can kick my but, but my car is plenty quick... without any modified efforts... =) "my time is money"

--Ariel<p>2001
225QR
No mods, yet!

VAP

In a 225/180 engine built identically then yes, the 180 would certainly generate more HP/torque by virtue of higher compression ratios. But with that higher CR comes pitfalls that need to be identified and tended to. I think part of the 256HP Jenner now enjoys as found on AWE's dyno is due in part to that higher compression ratio. My desktop dyno says compression ratio alone is a 15HP increase, but the GIAC chip has to account for something as well to put it over the 225 baseline. And he HAS to be sucking some exceedingly hot charge air into that engine with a K04 and only a single intercooler. Which can lead to all kinds of problems such as pre-ignition, detonation and the ECU always running in a retarded mode to save the engine. If he added a 2nd IC or a single large one he'd probably see another 25-40HP increase respectively and be running more efficiently/safer to boot... due to cooler charge air temps AND the chip allowing him more agressive timing/boost profiles.

I'd rather have the 225's lower compression and run higher boost than the 180's higher compression with the same boost. Its safer, more reliable power. Better yet, I'd love to have some 7.5:1 or 8:1 forged pistons made with a solid copper head gasket and run nearer 25lbs of boost.

The 180 as-is would be an easier platform with stock pistons and well-planned preventitive (engine-saving) tecniques in place to reach the 300HP mark. But the 225 would be a safer platform for that or anything beyond that due to lower CR as a stock-piston'd car. But to REALLY be safe, anyone considering 300+ HP should absolutely insist on forged pistons. It will ALWAYS be safer to get more boosted HP from a lower CR than a high CR block. And in as much as that, the 225 isn't really "stronger" so much as it is better engineered.

TTKEN

<p>TTKEN ;{
225TTQ SILVER/EBONY
ST.AUGUSTINE FL
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