ajrlredondo

Hello:

My name is Alex. I´m from Spain and new on this forum. I´m building a 951 turbo s rallye car. My project is to built an entire welded rollcage from the body
that previously went to acid tank to remove the paint. (I will put photos on this post). I would like to ask help on this forum that I have found and
I seeing there are many people who knows very wells that cars because I have a lot of questions about the engine. Sorry for the long chat and questions.

The project is to built a 3.0l aluminium turbo race engine with 8V cylinderhead and alusil treatment or other if is better.The hp target is to get +-350-370 hp reliable horsepower at 1 bar boost.

Engine

1º At present, I have 2.5 l turbo engine block and cylinderhead, turbo, waterpump,etc. By the moment I see most people use 968 block with
alusil treatment and 2.7 cylinderhead. Is that the best option for the block? and for the cylinderhead? because the 2.5 turbo cylinder heads has ceramic lines

2º For the block I would like to fit 968 crank lightened, titanium pauter rods, custom pistons with coated compatible for alusil (correct me if I'm wrong),
I´m not sure which brand I have to choose keeping the compresion ratio. Other problem I read is the shoulders of the bolts rods for 3.0l crank. Is this configuration Ok?

3º Tell me something about what crankscraper I have to use (the car is only for race)

4º Is possible to fit the 968 waterpump or 951 block

5º Can I fit oil squirters from any 968 engine block?. I have the spare parts catalogue 968 and I don´t see any diferrences about oil squirters. It doesn´t
appears on the catalogue!! or is there someone that make this modification??

6º Who can make the crank weight reduction??, balance, etc

7º Is neccesary to use the damper from 944 S2 engine block with this engine??

8º Is a good option to remove or cut the balance shafts?? and where??

9º the 968 cylinderhead gasket is good to use in a race engine or there is another one better??

10º where can I take the block to make the alusil treatment?? or who is the better proffesional or experimented people to do this??


11º which turbocharger dual ball bearing can I use for a fast response and 350-370 hp?? (GT30,GT28)?? Normal rpm range in this races is 4000-6000 rpm.

For that question I will use a 016R gearbox with LSD 8:31 ring and pinion and 3th,4th and 5th gear from powerhause with ratios 1,58:1(3 gear) 1,23:1 (4 gear) and
1:1 (5 gear), taht is 116,86 miles\hour at 6000 rpm with 64 mm diameter wheels.

12º which exhaust, downpipe??? and from who?? 3 inches, 4 inches?? I think 3" would be better for that horsepowers.

13º which wastegates. I´m thinking tial 46 mm to fit directly on the stock downpipe

I woul need the 968 engine block and the 968 crank to start. If you know any people who has this part I will buy and sell my 951 short block.

This is for the moment (and it is enough). For the future I would upgrade the cylinderhead.

Sorry for my english and thank you very much for all help you can give me.

Regards


Understeer is when you can see the tree you will crash into and oversteer is when you can heard it. Walther Rohl

Duke

Welcome!
Is your target 350-370 hp or is it to boost 1 bar?
350-370 hp on a 3.0l will require less than 1 bar of boost (unless the head and cam is screwed up) so that's a good thing

The 2.5l blocks have a 100 mm bore while the 2.7l/S2/968 blocks have a 104 mm bore. You want to start with a 104 mm block, they are better built than the 100 mm, and you can't bore a 2.5l block out to 104 mm so you need the larger block to build a 3.0l (unless you sleeve it).
A 2.7l head is bolt on but you have to replace the hardware. But since you have such a low hp goal set a stock refreshed 951 head would work just fine after a reshaped fron water neck.

Mahle and Wössner are probably the only good sources for alusil pistons.
The rod bolts are not a problem on the 104 mm blocks. Also, pauter and carillo rods should clear a 100 mm block girdle even with the long 88 mm stroke. If not, only a simple adjustment is needed.

Take a look here for scrapers and windage trays:
http://www.crank-scrapers.com/Porsche.html

The 104mm and 100mm blocks have different pumps.

Yes you can, but not without machining the block. So if you do, you can start with any type of squirter. From a 993, BMW etc.

Any good engine machine shop should be able to do it.

It's a good idea if you put reliability before maximum throttle response.

See above regarding keeping them.

A Cometic MLS headgasket is "better", but requires perfect conditions such as perfectly flat head and block etc.

Not many places can hone or bore an alusil block. If you want to look around locally, try looking for a place that does work on Mercedes engines.

A GT2871R will be enough if you want to keep the power below 400 hp. That means ultra fast response.

3" is enough for your goals. Lindsey Racing and Speed Force Racing both sell downpipes and exhausts.

A Tial 46mm will work fine, but I personally like the Tial 44mm v-band better.

I will send you a PM.

JohnKoaWood

Hello and welcome to the place to get those answers, I will try to give you a few, and they might be wrong..I am sure someone will jump in and correct me If I make a mistake...

Some times it is easier to get replies by keeping the questions to 1 or 2 per post, but we will see what we can do for you...

968 or 944S2 block is prefered as they are already 104MM bore x 88mm stroke.
2.7 head is the easiest of the 8 valve heads to bolt on, but the 3L head also works if you find a complete 3L engine use it.. the 16V head can outperform the 8V head...

again, a 968 or 944S2 crank will work, they have different harmonic dampin systems, so you WILL have other components needed such as the S2 front pulleys vs 968 dual mass flywheel... you will need low compression pistons, multiple vendors offer lower compression pistons in the 104mm size... find a block, have it machined, then worry about the pistons... else you risk buying a set of pistons you won't be able to use and at more than $1000 US, that can become an expensive mistake...

The connecting rods MAY have to be machined to work, but if you start with a 3L block you should be fine as long as you get the proper rods for the block... the issues arises when a 3L crank is used in a 2.5 L block, the con rods get VERY close to the block wall...

http://www.crank-scrapers.com/Porsche.html

944.106.003.00 is the 968 , 944.106.021.13 is the water pump used up to 86, 944.106.021.22 is the 87 and on 944 / 951 pump...
Oil squirters are a feature that has to machined into the block... contact a machinist to have this done, once you have a block to use...

any decent machine shop SHOULD be able to, Lindsey Racing, 944 Online, and several other online part suppliers offer them, with services to either their crank that you buy, or your crank that you send to them...

I'm going to assume you mean the front pulley, as it is a harmonic damper on the S2... it will depend on which crank you use... the crank will need to stay with it's designed damper (dual mass flywheel in the case of a 968 crank)

100% race car, sure remove them, and plug the holes..Lindsey racing has a balance shaft delete kit...

2 different ones out there, widefire and cometic... for your HP target get a widefire and forget it...

Don't know about spain, but in the US there are several shops more than capable... shipping MIGHT be prohibitive, but you could always check to find out... for what it's worth, a stripped block is about 50lbs I believe...

KKK 27-8, LR super 48 will get you there, or Vitesse racing... or a custom house can get you where you want to be...

Um... is there a question here, or asking for reccomendations? I would reccomend a 968 6 speed, or STOCK 951 with a taller 5th gear..(.83:1 or less...) why goto a 1:1 5th... sounds like it would be a slow race, or you like shifting A LOT... is this car going to be Auto-Cross only, or road race?

If road race, get the taller gears, not shorter... you want higher top speed, and more use of the gears in your power band, the ratios you list would give you the opposite...

remove any and all restirction behind the turbo you can... 3 inch should suffice, but if you can get 4 inch for the same price why not go 4...

46mm Tial will give an ON-OFF feeling to your boost, and give horible boost pressure support at higher RPM.... for 350 HP, stick with a 38mm Tial or simmilar size from whichever supplier you like... you will get smooth action in the WG opening, and smoother boost response...

There are at least 2 I know of for sale right now...

1 in on here in the thread titles "parting a 92 968..." I believe he is asking for $1600US for the complete block..if you want to have machining done in the US, I am sure he could reccomend a machining house and shipping to them from him to save you a little money in the entire deal...

Good luck, I am considering a simmilar build this winter, but with a little higher HP goal... in reality 350 HP is a LOW target to hit with a 3L build up, but it should make for a very reliable engine...

JohnKoaWood

Damnit you beat me to him...



I also think 350 is a low target for a 3L build, but hey..I bet it would last damn near forever...

Duke

With a post that long to answer it was destined to happen

V2Rocket

what a beast

gt37vgt

consider sleeving your block .

lighting the crank effects the way the crank scraper works so consider the 2 things at the same time ... you have to make one to suit the other ...
yeh 3" will do it but 4" is better even at lower power levels ..
gt2871 will do it next one up is gt3076 would be my choice
Ti rods are very expensive bragging rights and over kill
taking some more weight out of the valve chain seems more cost effective to me than fancy rods as the valves are clunky..

there are guys on here that can help with details of good chev race valve conversion

for your conservative power goals i would err toward higher compression than other builds to make it nice and responsive ..

JohnKoaWood

and last a lot longer...

333pg333

Look to dry sumping it and don't worry about the crank scraper etc...
That's a really low power figure to aim for too. On a 3L motor you could put a GT3076 and it would be extrememly responsive, but really a GT35 would be more suited except you will exceed your desired power figure by a fair bit. Just ask Duke.

evil 944t

[QUOTE=JohnKoaWood;6909239]
46mm Tial will give an ON-OFF feeling to your boost, and give horible boost pressure support at higher RPM....QUOTE]

not true.

Tom M'Guinn

Bienvenido a Rennlist! Su inglés es mejor que nuestro español, sin duda.

Re the 46mm Tial, that is what I use on my 3 liter and it works great.

Check out the 3L registry thread at the top of this forum -- it lists the various configurations people are using for their 3 liter motors.

350-370hp on a 3L is a modest goal, and you should be able to get their and make it very reliable and long lasting at that level.

A few things not already mentioned, You need special studs to run the 8v head on the 104mm blocks. Raceware sells them, but does not advertise them. Or you can use 1989 2.7L studs.

You need to use 951 exhaust valves in the 2.7 head.

Stripped block weights 65 lbs.

Vitesse stage 5 turbo would give you a nice flat torque curve. Mine make 1 bar at 3k rpms, and recently made 500/500 hp/torque with a stock 2.7 head.

You didn't mention engine management, so I'd just mention that Vitesse's chip board and MAF offer spot on 3L tuning right off the shelf. No sense risking your motor by trying to self tune a brand new motor.

V2Rocket

no cierto, a veces mi espanol es mejor que mi ingles

Olli Snellman

Most of the parts you need can be found from European suppliers. For example Deutsch Nine's Beni have a brand new 968 block & crank for sale. I also have several 104mm blocks & cranks available, like also does Duke/Gustaf in Sweden. If you cannot locate a company who can Alusil jobs, there's a company in my home town which has done Porsche Alusil treatments over 20 years.They charge 100€/cylinder. They also install oil squirters to these blocks. Want to buy a 104 mm block with new alusil & oil squirters installed ?
Some time i find it out funny when us europeans bought all possible "tune" parts from the States when all possible know how is also available inside EU countries.
I would no go to titanium con rods, according to my con rod manufacturer titanium is nice but there are "working hours" after which rods must be cheked. I use his steel rods.

Here's several parts i have used with my build up









And Welcome


Why? I have Chevy big block valves both intake & exhaust side.

DANNiE

All that work sounds like a bit of over kill to me... Just to get 350 HP...

If the car is already Turbo; wouldnt it just make sense to upgarde the stock 2.5L unit to get to 350HP..?

Id say if you must need more displacement... Stroke it with a 2.7L crank...

Get more power with a larger turbo and exhaust system and chip setup...
Mod the intake side too with a larger intercooler and piping setup...
And larger fuel injectors...

Im sure with the above mods alone you could hit 350HP on the 2.5L block alone... Id throw in a set of Raceware Head studs to keep the whole thing from popping apart under serious boost but that about it...

Olli Snellman

= S2 crank.

2.7L is just a 2.5L block & 3.0L crank combination with suitable pistons.