Pros/cons VX red top vs Duratec 2 litres

[StanS]

I did my own rebuild on a 2.0l Duratec which consisted of standard pistons pocketed, standard rods, piper 285 cams, light DIY head porting, keywayed crand & pulleys, ARP bolts througout engine build, 90mm trunmpets and a raceline exhaust. the engine had done 6k miles when this was done and gave 226bhp with a 7500rpm limit but was still climbing on the power curve and Troy suggested raising the rev limit due to ARP bolts and it would hit 230bhp but i left is at 7800 for comfort / standard rods & psitons.

 

Having recently sold the car, the new owner plans on racing it and had it an a rolling road to check fueling etc before racing and he was plesnently suprised when it gave 241bhp at 7500rpm, the increase is eaother down to the engine now being bedded in at 15,000 miles or difference in r/road set up, either way it gave at least 226bhp for resonable costs.

As a matter of interest, how much approx did the rebuild cost (parts) ?

[exboeingboy]

You have PM.

[Pistol Pete]

Stan, get yourself a passenger ride in a 200bhp westfield, due to the lack of weight no impreza* can ever give you the sense of engine dominating the car than a Westfield (other sevens are available) and general lack of weight!

 

* I drive have a standard WRX as a tintop and used to sprint against some powerful ones

 

I actually think you need a run out with some of the Cambridge area members - it will focus your mind.

[Speed Freak]

Ive quoted this before, but I have an s2000 powered westy with its original transmission-its not ideal as its not close ratio enough-even still, it will do 0-100 in about 8.5 seconds ish (try and do that in an impreza  )... Im convinced that a 200hp lightweight westy (duratec equivalent) with the correct gear ratios would be just as quick to 100----

perhaps mine will be quicker after that, but who wants to do 130+mph in a westy???

[peterm135]

From memory, a Duratec can't be re-bored to the same extent as an XE can, Price wise, to get power will cost similar amount for both engines. 

Not that you want to be taking the engine apart every year or so but something to think about, if a problem ever arose.

 

Lifted from SBD WEBSITE 

Question: Do you have a piston for that with a Duratec 89mm bore?

Answer: We only manufacture two piston sizes for the 2.0/2.3L Duratec. We produce either 87.50mm to replace the standard piston in a standard bore or 88.00mm piston so the bore can be cleaned + 0.50mm oversize. The reason we do this is because the standard liner, which is cast into the Duratec block has been specially developed by Mazda/Ford. We have looked quite closely at replacing this liner because we get regular requests for bigger bore sizes, there are several problems;

1. The liner is very thin, which allows it to expand and contract with the aluminium that is cast around it.

2. The modern Duratec engine has not been designed to be rebored at any time in it's life, therefore the thickness of this liner is calculated to be correct at the 87.50mm bore.

3. We made a decision due to the design of the liner to allow only the smallest of rebore sizes to rectify a small amount of damage to the liner itself, this was the reason why we picked 88.00mm.

4. If we were to increase the bore size greater than 88mm, the liner thickness would become too thin, in our opinion, and over time would begin to disort.

5. Many of our competitors have not, in our opinion, taken this into account and although your engine may run successfully for a short period of time depending on use, eventually problems will occur creating premature engine wear and eventually failure.

6. Several companies have been replacing the liners, when the original liner is replaced there are several issues; the thin construct and ridged shape means that a lot of material has to be machined out to remove the original liner. This then means the aluminium left, particularly between the liners is very thin. The liner that is then used has to be off a completely different constuction as it needs to be more self supporting, which is fine as far as the liner is concerned but the issue that arises is the thin layers of aluminium that expand and contract around the new more rigid liner are too thin and expand at a different rate to the now more rigid liner so again initially the engine will run ok, but the feedback we get from customers who have tried this option find failure seems to always occur in the short term in high performance engines but this takes a little longer on a road based engine.

Although there may be a way of overcome the issues with replacing the liners, I believe the only way to do this successfully is to redesign the interior of the block completely, but this would be a very costly exercise and therefore should only be undertaken on turbo engines over 500bhp. It would actually be cheaper to replace the complete engine than it would be to carry this kind of work even when once developed properly.

So my suggestion would be to go with either the stock or +0.50mm version and if you are engine has more damage than that, that the block is replaced.

[Norman Verona]

A chap used to come into our local and he had an aged Impretza. He always claimed his car would go faster than mine and also corner quicker.

 

One day I took him out in it. Never saw him again.

[Speed Freak]

A chap used to come into our local and he had an aged Impretza. He always claimed his car would go faster than mine and also corner quicker.

 

One day I took him out in it. Never saw him again.

hehehehe that made me laugh.

[StanS]

I remember my 150 BHP S3 L7 and my recent 430BHP Classic Imprezza and 460 BHP Hatch, which would do 60 in under 3.5 s and 100 in about 8.5s. If anything the 430 Classic, being lighter, felt more brutal in acceleration although similar performance. The 4 wheel drive rocketed the car forward from rest, especially with R888's where a lot of 2 wheel drive cars initially struggle to get the power down without wheel spin. Fairly lightly modified Scoobies are not hugely quick due to their weight.

But most young guns believe their current car is a world beater ! Age brings experience and perspective

This guy supplied the turbo on my Classic back in 2002. 4 wheel drive putting 900BHP down effectively !

 

 

Interesting input Peterm135 - thanks - more stuff I didn'r realise !!.