Raceboy

I can tell you guys that my 2.5 16v Turbo build together with intakes, exhaust, turbos, headwork, etc will cost LESS than 10 000 usd.
For those who are interested what and how I am doing it, search my posts here in Rennlist.
Of course, I'm doing most of the work myself (sans headwork).

And it's me who flycut the stock 951 pistons.

docwyte

MooreBoost, NASA doesn't care what motor you have in the car, it's based on power to weight. So be very careful about what you decide to do, as you might find yourself in a class where you're going to get your *** kicked.

I instruct with NASA Rocky Mtn, and recently went through this process with my LS1 equipped 951. Drop me an email and I'll fill you in on all the details that you need to think about *before* you embark on your project.

blown 944

How close to getting it running are you?

I also think it can be done for a reasonable price if you can do a bit of fab work.

schip43

Estonia! Wow!
Not sure why you can't post a link but I'll find it! Saw the fly cutting deal pretty cool!

schip43

Hmm everybody defines reasonable differently, 10k is not reasonable to me. Under 5 is what I'd consider reasonable with the manifolds done, is that out of the question? Pistons and rods I was gonna change out anyway, I'd like lighter parts than the stock Tiger Tank weight items so pistons and rods part of the build but factored out for a project cost!

So is 5k doable?

67King

Thanks for chiming in. I'm in the collecting parts phase. Supposed to pick up an S engine next week. Have the turbo and PCM. I'd seen your "flycut" thread, and had seen folks do that before with bigger cams or valves, but never a chamber shape change. To my question - what valves are you planning on using? Are the stock ones up to snuff?

MooreBoost

i was told the stock valves wont work. i dont think they can hold up to the heat.

schip43

You could cryo treat the stock valves...then let us know if that worked!

blown 944

In regard to valves, I don't personally know what material they are made out of. But I do know that sometimes a source may be just assuming that materials won't work even though they will. My example would be; ceramic exhaust liners. It had been told to me many years ago that these were necessary to build a turbo engine. I'm pretty sure everyone who has built an engine here understands that while they are nice, they are certainly not necessary. Again sodium filled valves may bey nice but are not exactly necessary either if the ss material is high enough grade and egt's are kept on check.

schip43

But if you look at...well yeah I guess your right!

schip43

Wow, it's hard to be original on this board but I found more stuff and it looks like the 944 S head is the "easiest" if that can be said!

https://rennlist.com/forums/944-turb...lve-951-a.html

gt37vgt

i think it all depends where you starting from ... and exactly what you want ..
it only adds cost effective if you stumble across a few parts like a2.5 S complete for under $ 800..
or some kind turbo you like that would require custom install
i think its a much better idea than dropping 2or 3 k on a solid lifer stage 4 8v set up. wich is basicly trying to get an 8v perform like a 16v
i think a low boost e85 turbo conversion on a 944s 16v is a good idea

Chris White

Its been done quite a few times. In fact here a video of a dyno test on ‘Wormhole’s’ 2.5 16v.



The ‘Good’ reasons for building a 16v 2.5 –
The cylinder head bolts on to the 2.5 block with no modifications (water passages line up)
The head is usually cheaper than a 3.0 16v head
100mm bore is more ignition timing ‘friendly’
Class racing rules for PCA GT may keep you in a lower class
Looks pretty cool!

The “not so good’ reasons for building a 16v 2.5 -
The cost of a 2.5 is not much less than a 3.0 – the crank is the most of the cost difference
You need custom intake and exhaust manifolds
Custom pistons
Custom valves and valve springs
Engine management mods

Quite few opinions already on this thread – here are some more!
The level of mods is, as always, highly dependent on the end use of the engine. If this were for a track engine I would say that better valves are mandatory. I use custom valves that have a 2200f temp rating. For a race engine I would get the combustion chamber and the exhaust port treated with a heat rejection coating. Stiffer valve springs are also a good idea for a tack car – the stock springs are not very strong and the added pressure on the intake valve will not help. You can skip all the head mods on a street car and it will survive if you don’t beat the snot out of it.

As mentioned before – I have a set of 100mm 16v alusil compatible pistons sitting in the shop right now….customer changed his mind after they were made – I could be ‘flexible’ on the price!!!

gt37vgt

"custom pistons valves and valve springs "
I don't get it chris ..
at full lift the valves are only protruding about 2-3mm from the head (2.5/16v)
and at a guess that it's no where near TDC
so although its nice in the case of a belt failure surly it can run without valve reliefs ??? therefor ruglar 944 turbo pistons ?
and customs valves and springs why ?
also wouldn't the knock resistant nature of the 16v head make the increased compratio yielded with smaller head cc ok ?

Paulyy

That's what always comes to my mind. but for somereason i always think of the 944s head i think of the chain tensioner failure on those heads. but i'm not even sure if the chain tensioner are the same as the s2 or 968 heads. because when i look at used 944s heads i always come across the same issue.