roman944

yeah I saw that, he also says that they were made to work with 106mm pistons or something ... would that work on the stock block?

I sent him a message/e-mail so I hope to hear from him, wonder if it comes with valves and springs already installed too?

might be a good deal regardless.

Tom R.

Dont sell them. trust me. you will want a set of four 16x8s for track tires. if you are going to run 7&8s for track i may have a set of 205/225 R compuond tires for you soon, real soon.

roman944

I'm working on the pics of the spacers, I'll have them tonight, and will probably measure the spacers and come back with results

as of now, what exactly happens when the engine gets turned over w/o a belt on? there aren't any noises coming from it, can someone explain maybe a tad in detail?

Mark944na86

Crankshaft goes around. Pistons go up and down in cylinders. Any valves that are open would normally be closed and out of the way of piston at the top of each stroke by the action of the camshaft rotation. But no cam belt, no camshaft rotation. So instead, valves stay open, argue with pistons over who's going to occupy space. Pistons win, valves bend.

That's why it's called an interference engine. If there are no noises coming from the engine as you turn it over, that's because the valves that were in the way no longer are.

theiceman

Some strange things going on here for sure . i you sure you posted correctly about your tire sizes ? if so you have two different sets of wheel sizes. They should all be the same. Do you really want bigger wheels on the back than the front ? You should have tires matched to the rims so the over all rolling radius of the wheels is the same.

You should have
205 55 16s on the front and 225 50 16s on the back. This will give you matched wheel sizes. Your wheels and tires are completely mismatched and I would not spend any money changing anything to anything until you understand what you really want.

roman944

Mark - thanks for taking time to try and hammer this into my head, I just don't know how to explain it to my dad; we have a 2.7T Audi A6 with interference engine in the garage with a shot head, and that engine does not turn over at all, but its a V6, Porsche on the other hand is not a V4 - so he says that Porsche should be fine compared to the Audi

=====

iceman: the tires I got free when my rear tires wore out
the wheels came with the car, and from P/O I didn't get any info on the car; I didn't know if they are real or replicas, I didn't know offsets or sizes; so when my rear tires wore out, I assumed that all wheels were the same size - and the shop that put the tires on did not tell me that the wheels are different sizes (and I failed by not asking them about it); so when my rear tires wore of, a friend of mine gave me a set; it used to have 225/50/16's on all 4 corners; my friend has a Chevy Impala and his tires were 225/60/16 (same as on Pontiac Bonneville etc.) so he gave them to me for free

I didn't know that my front wheels and rear wheels were different sizes; and with cold weather, I finally got to take them off and went looking for any numbers stamped on them - and thanks to the picture provided in one of the first posts, I now know what size and offset they are

at this point, I think I need to think about what I want to do with the wheels; here are the spacers that are on the car right now, all 4 on all 4 corners are the same size - I measured them just n ow and took a picture of one:





the spacer by itself measures 1 3/8", which is quiet big in size, but the wheels are lined up perfectly wtiht he fender in the front, and a tiny bit (maybe 1/8") into the fender in the rear, but they look perfect

I know my tires are "mismatched", the rear tires look really bulging, its kind of funny - but you can see in the picture how it looks, its "meaty"

so now, I need to figure out what to do with the wheels/tires. is it safe to run spacer THAT big? should I attempt to sell the wheels and get something with correct offset? or maybe trade for a set of wheels with correct offset? I don't even know what these wheels are worth

=====

the wheels do look good, and I do like them, I want to take my car to some autocross races and maybe do a couple DE events; ofcourse getting it fixed and runing is the first priority, so at this point I am looking for a good/used/rebuilt head, or should I attempt taking mine off and rebuilding it?

theykallmekem

those are ******* HUUUGE you werent kidding us

theiceman

holly crapers . those studs must be like long as hell.

Sounds like you are getting a good handle on what you have . I know on the 91 mixing tires can have disasterous results, I don't remembe having too much issue on my 944. Personally i would go bak to stock wheel sizes that the car was designed for but it is easy to say when you are not forking out the bucks

Good luck .

BTW interference engine of course has nothing to do with engine configuration such as " V" "inline " or horizontally opposed "

interference is all about getting high compresion ratios for power fuel efficiency and pollution control.

roman944

well, aparently, "effective" offset is right at 20 in front and 17 in rear after the spacers (35mm spacer), so I guess its puts me right around where I am supposed to be?

I am worried about breaking something or wheel flying off

whats the difference between hubcentric spacer and not? how do I tell? what do 944's need? if I keep this, I want to get this atleast right ... offers? opinions?

if I keep them, if its a good idea, I'll have them painted black with red lips

Mark944na86

Roman,

The 225/50/16 will be the right diameter for your car, but the 225/60/16 won't be.

To calculate the diameter of your tire (in mm), apply this formula:

d = (R*25.4) + 2*(W*P/100)

where d is diameter, R is rim size (in inches), W is width (in mm), and P is the profile. Like this:


.W. .P .R .d.
205 55 16 631.9
225 50 16 631.4 <-- these 3 approx. equal
255 45 16 635.9

225 60 16 676.4 <-- way too big

As you can see, as the width of the tire increases, the profile has to decrease to keep the overall diameter approximately equal. And yes, the W/P/R system for sizing tires, which mixes inches and mm, has got to be among the stupidest systems ever invented. But anywho...

On 7 front and 8 rear, I'd suggest 205/55/16 front and 225/50/16 rear as reasonable choices.

DSMblue

Completely agree - the 16x7's should be on the front, 16x8's out back. Alternative tire sizes are 225/50 16's front, 245/45 16's rear. For an NA, that's a lot of tire for the engine, and adds cost. If you are setting up a dedicated track set, many people do run 16x8's all around. Definitely do NOT rotate different rim sizes under any conditions.

roman944

Mark - yes, and with 60's in this size, I end up with a lot of extra unwanted sidewall

can anyone comment on the spacers? safe or not? I haven't had any trouble, but with a spacer this large, should I be woried about excessive wear on bearings/brakes/shocks? I doubt it will be much, still

I think 245/45 would work out nicely - and I'm not worried about rotations or anything like that; also, right now, I'm slowly starting to take things out of the car; for now - everything from front seats -> back, all the trim, rear seats, spare, tools, everything; my car has that removable roof - I'll be taking it out during the run; I've been thinking of geting the A/C delete bracket and taking out the A/C because it doesn't work anyways (might need a charge, but its not upgraded anyways)

the only thing that worries me is, how will these tire sizes work out once the car gets lowered?

I had another question, why would my car work worse on 87 or 91 gas, but work perfect on the 89?

Mark944na86

I would think 245s would be definitely too wide for 7s, and possibly too wide for 8s on back.

Why do you want to go so wide? Just for looks? 205 front and 225 rear will give you more than enough rubber for an N/A.... hell, that's was the stock fitment for an S2!

roman944

well, 205/225/245 are all my options

225's to match the other tires
205's could go in front and 225's I have now in rear
245's to go in the rear

I want the car as stable as possible, as much grip as I can get; looks like either 225 or 245 will work; from doing a search it appears 245 is a good choice if it fits without rubbing, and they are made for something like 7-9" wheel; 225's are made for 6-8" wheel

I'm all open to suggestions, for or against though, search on Google yields a lot of results, but mostly because its a tire size, so the minute someone mentions it ... it shows up even though it has nothing to do with what I'm searching for

thanks

fbgh2o

Stock sizes for the turbo on 16 x7 &8 are
205/55R16
225/50R16 respectively.

I agree with Mark on his selection (plus there is a alot of options for tires in those sizes). You definitely do not want a 60 profile.