Astra gsi 156hp & 106 gti

[y@sin]

106 geçecektir..

[fatiii]

Havalar ısınsada denemeler başlasa

ankarada olsaydın senlede ben denerdik

[zıpzıp]

106 gti alır

[tolga.k]

ankarada olsaydın senlede ben denerdik

Acemiyim daha

[fatiii]

Acemiyim daha

bende

sadece düzde basıyorum

[aLperTunga]

her türlüü 106 alırr..

[tolga.k]

ben düzdede basamıyorum hesapla işte

[fatiii]

ben düzdede basamıyorum hesapla işte

o zaman dikkat et makina sakat

[burock]

deneme nerde olucak acaba?

Ankara da olursa haber verselerde burdan canlı canlı izlesek

[vkarayel]

400 de gti, 800 de gsi gibime geliyor astra 3. vitesten sonra uzamaya başlar kanımca ...

[fatiii]

Ankara da olursa haber verselerde burdan canlı canlı izlesek

hatta izlemesek bizde denesek...

[burock]

hatta izlemesek bizde denesek...

deneriz gsi ile hiç üstüme alınmıyorum

[ufuck]

bız denedık 106 adı 0-400 ama

[Sefa_vts]

Hertürlü 106 yazan arkadaşları kutluyorum.. Fanatikliğe gerek yok.. Ben de 106 sahibiyim..

Sağlıklı bi gsi sağlıklı bi gti a geçilmez.. En azından roll de diyelim tartışma çıkarmamak için..

[pasa35]

kalkısta plotajın bı nebze daha onemı oluyor rollde gsi alır heralde 0-400de 106 diyorum

[gsi_club]

pilotaja baglidir.arabayi iyi kaldiran yürütür isi.iki araç ta stock ise ne olacagi bilinmez.bu arada astra f gsi sfi motorlu araçlar 150 hp dir 156 hp degildir.156 hp olanlar cosworh kapakli olandir.Türkiye de zannedersem yok denecek kadar azdir.

[Alperen-B]

pilotaja baglidir.arabayi iyi kaldiran yürütür isi.iki araç ta stock ise ne olacagi bilinmez.bu arada astra f gsi sfi motorlu araçlar 150 hp dir 156 hp degildir.156 hp olanlar cosworh kapakli olandir.Türkiye de zannedersem yok denecek kadar azdir.

benim bildigim bi kolbenschmit bi de coscast. yani 2 kapak var diye biliyordum. cosworh
u yeni duyuyorum

[renault_f1]

stock gsi sfi ile stock 160lık HB VTİ 0-400de kafa kafaya gidiyorlardı stock verilere baktığımda 106 daha yawaş gözüküyor 0-100 süresi olarak felan ben GSİ diyorum ama pilotaj büyük etken tabiki we araç durumu tartışmasız...

[VeNoM_35]

şu cosworth ve 156 hp olayına açıklık getireyim de, yanlış yorumlar yazılmasın

This is by no means meant to be a definitive guide to the Cosworth produced 20XE cylinder heads, i'm just collating all the stuff i know into one pile and hopefully it should go some ways to dispelling a few myths and answering a few questions about the illustrious chunks of metal! The main two points of discussion seem to be that the head produces more power than the GM variant, the other discussion banded about is that Coscast heads are not prone to the infamous 20XE porosity issue.

So the story starts back in 1987/1988 when Vauxhall decided to develop a range topping 2 litre 16v double over head cam engine for the forthcoming Astra GTE16v. It was based on the current range topping 2.0 8v family-2 engine block with changes to the crank, rods and pistons. The first major point is that Cosworth did not design the cylinder head. To my knowledge they had no involvement in the design process at all. The 20XE cylinder head was penned by Opel advanced engine development, lead by german born chief engineer Dr Fritz Indra. I think the confusion was fueled by the fact that Cosworth had previously designed and produced heads for the 70/80s CIH engines, most notably motorsport and road going heads for the 2.4 manta 400 power plant.

So, where do Cosworth come into the equation ? Well simply, Vauxhall commissioned Cosworth to produce the original astra cylinder heads at much cost I might add. Infact, Dr Fritz Indra’s approach to whole engine was one of complete perfection with little regard to cost. How he managed to convince the number crunchers at opel is beyond me. It bares testament to the units over-engineering, the fact there are thousands still going strong and being tuned further, 10-15 years later.

Designs built in large numbers are often spoiled by insufficient attention to detail, he says - a four-valve head is wasted unless every other part of the engine is carefully optimised to exploit its breathing potential and combustion efficiency. "You must have the best induction system, the best injection system, the best exhaust system, the best ignition system and proper knock control." In some rival four-valve engines, he says, the potential for free breathing is thrown away by the use of an intake air cleaner of the same size as for the two-valve variant

The trade mark “Coscast” is a licensed method to produce quality castings, molten aluminium is pumped into an inverted high quality mould made from a grade of zircon sand, via a sealed crucible. Crucially the same grade of aluminium was used for both the later Kolbenschmidt (see below) produced heads as the Cosworth heads (LM25TF with the TF being the brinnel hardness range). So the only difference was down to Cosworths comprehensive casting method.

Now, this is where my info gets a little vague as I don’t know the exact reason, but, late in 1989 GM dropped the contract with Cosworth and farmed the production of the cylinder heads out to the german engine manufacturer Kolbenschmidt. Using the same design as the original Opel head but utilising their own inferior casting process, they then pumped out heads in their thousands between 1989 and 1993, so basically late GTE’s, and mk3 Atras/Cavaliers. A second run from cosworth was produced later in 1993, and cars from that date onwards had either type fitted.

So what is porosity? well, despite what the name suggests its nothing to do with the metal becoming porous (allowing water to seep through its microscopic structure), it is infact a physical crack between the main oil channel in the front centre of the cylinder head (between exhaust ports 2+3) and the coolant gallery above cylinders 2+3. In the Kolbenschmidt produced heads, the cast was too thin in this area, in some cases critically, and the alloy was slightly harder and thus brittle, a combination of concentrated pressure from the front centre head bolt and the extreme cylinder heat below, this forms a crack in the alloy allowing oil to enter the coolant passages. Then you get the trade mark mayonnaise in the coolant system as oil and water mix together with resulting confusion that its a head gasket failure. On this premise alone it is still possible for a coscast head to go "porous" but its infinitely less likely due to the casting being thicker at the key point and the alloy itself being physically stronger. Vauxhall never admitted liability for the failures and there was never a proper recall for the fault, but, any car that came in with this fault under the manufacturers warrantee was fitted with a tube repair in the oil gallery or an exchange Coscast head. Aparently post 1993 Kolbenschmidt heads had softer alloy structure, added to the porosity issue, its rumoured this is why Vauxhall altered the method of tightening down the XE/LET head bolts from the earlier 5 stage sequence to the later 4 stage sequence. Later engines also were fitted with short head bolts from the factory.

Whats the difference between Kolbenschmidt and Coscast heads and how can I tell which one I have ? Apart from the porosity issue described, the heads are virtually identical. There is an exception however, the early astra heads between 1988-1989 had hand finished inlet ports from the chamber all the way to inlet manifold, they also had 2mm bigger valve guides, and slightly deeper valve seats, they also used dish shaped valve springs seats as opposed to the later flat disk. The later coscast heads after 1993 were same in specification as the interim Kolbenschmidt heads, basic machining around the valve throat is all they got. The port finish was just left from the cast, almost like the complexion of orange peel. As mentioned earlier, the early pre catalysed 20XE engines made 156bhp from the factory, purely by coincidence the Kolbenschmidt cylinder heads were introduced at the same time as factory fitted catalysts and the power dropped to 150bhp. Needless to say ever since rumours are bound that the power difference was due to Coascast heads being better, this simply isn’t the case! The catalyst sapped the power.

The most definitive way to tell if you have a Coscast head is to look under the 2nd exhaust port along from the cam belt end of the engine and you will see the coscast oval. Clearly visible if the head is on the bench, or its still possible to see with a small vanity mirror held under the exhaust manifold…


Alternatively there are distinct casting differences such as the posts that the engine lifting rings bolt to, and the exhaust heat shield bolt to, these are U shaped on Coscast heads and just round posts on Kolbenschmidt heads…


Also on the distributor end of the head you will see a tapered hole and a distinct Z shaped ledge along the side of Coscast heads…



Note also in the above picture the head is plain cast at the distributor end. On Kolbenschmidt and post 1993 Coscast heads it will have a GM stamp and GM part number there in raised lettering. So this particular picture is the nicer early gte head.

The following chart is a guide to the production dates and types of head fitted to different types of car. Kadett-E being mk2 Astra, Astra-F being mk3 Astra, Vectra-A being mk3 Cavalier. Note this is just a guide to the heads produced during those periods, its been nearly 15 years since the engines were first produced and the amount of mixing and matching will be widespread by now. So some cars made after 1989 can and do have Coscast heads.