Scaley 0 Posted March 27, 2010 Report Share Posted March 27, 2010 Hi,As the title was wondering how much it would cost to have my blocked bored to 2.9 as Ive stripped it and its not in the best of shape so thought I might as well go the whole way!Also I was going to rebuild it with forged pistons, I take it if I go with the 2.9 bore I can use standard size corrado pistons?Any help would be great full! Cheers Mike Link to post Share on other sites
golfrabbit33 0 Posted March 27, 2010 Report Share Posted March 27, 2010 weakning cylinder walls is, imo not the best way to go. get a expert cleaning and light honing of the cylinders would be best. cyro treat the rods and your ok to 450 bhp, or was you looking at more power??. upgrades will have be made if you go over 500ft of torque Link to post Share on other sites
Scaley 0 Posted March 27, 2010 Author Report Share Posted March 27, 2010 Ah I thought 2.9 would still have good wall thickness, I will stick with 2.8 but Im sure its going to need a slight overbore maybe 0.5 it has to be reliable for a whole seasons racing!The whole engine is being rebuilt and upgraded so I can hopefully expect around 700bhp-ish not sure which turbo to go for yet I think a GT35 will be at its limit at this power range!Might be a better idea to use a 24v head for flow, does an R32 head fit or do you have to use the 2.8 24v head?Cheers Mike Link to post Share on other sites
redeye 0 Posted March 28, 2010 Report Share Posted March 28, 2010 ive read on a few forums about reboring to 2.9 weakens the bores ? ..... i dont believe it myself going from stock 81mm bore to 82mm is only skimming half a mm of the bore wall so there is still plenty of beef left on them Link to post Share on other sites
golfrabbit33 0 Posted March 28, 2010 Report Share Posted March 28, 2010 im sure you cant use a 24v head on a 12v obd 1/2 block. chime in anyone.... Link to post Share on other sites
Scaley 0 Posted March 28, 2010 Author Report Share Posted March 28, 2010 If you look at the 034 Motorsports site they have done it, or maybe it was a 4 motion engine? Link to post Share on other sites
golfrabbit33 0 Posted March 28, 2010 Report Share Posted March 28, 2010 Mike, speak to c2 motorsports.uk they will point you in the right direction,and they know what there talking about rather than me giving my limited knowledge. 700 bhp needs to be done right the first time . and they can sort your ecu to run your turbo set up.ps i run a gt35r at around 400hp Link to post Share on other sites
CALICO 130 Posted March 28, 2010 Report Share Posted March 28, 2010 try a qoute from tsr Link to post Share on other sites
Phat VR6 3 Posted March 28, 2010 Report Share Posted March 28, 2010 24v head can't go on the 12v block technically boring it out will make it weaker... and if your aiming for 700bhp it would be nice to keep the wall thickness.how many miles has it done? Link to post Share on other sites
bungy 2 Posted March 28, 2010 Report Share Posted March 28, 2010 700bhp Link to post Share on other sites
matty.vrt 120 Posted March 28, 2010 Report Share Posted March 28, 2010 I make 512lbs of tourque with standard rods no problem. Link to post Share on other sites
matty.vrt 120 Posted March 28, 2010 Report Share Posted March 28, 2010 garrett gt3582r is good for 700 bhp at 38 psi Link to post Share on other sites
legvw 0 Posted March 28, 2010 Report Share Posted March 28, 2010 Thats alot of horses! Link to post Share on other sites
RAPgolfvr6182 2 Posted March 28, 2010 Report Share Posted March 28, 2010 carnt you just use a 2.9 corrado bottom end? as said boring out would weaken it to much Link to post Share on other sites
redeye 0 Posted March 28, 2010 Report Share Posted March 28, 2010 carnt you just use a 2.9 corrado bottom end? as said boring out would weaken it to muchmy buddy had a 2.8 and a 2.9 block in his garage i will measure the wall thickness on both but im sure they are the exact same block hence the 2.9 bored out slighty Link to post Share on other sites
RAPgolfvr6182 2 Posted March 28, 2010 Report Share Posted March 28, 2010 to be fair to make 100cc over 6 cylinder i wouldnt have thought the bore would be much different Link to post Share on other sites
markiev6 1 Posted March 28, 2010 Report Share Posted March 28, 2010 the 2.8 and the 2.9 are the same block Link to post Share on other sites
Scaley 0 Posted March 28, 2010 Author Report Share Posted March 28, 2010 Cor a lot of info cheers guys!The reason for the rebore is the cylinders are not perfect so I will get away with the smallest bore I can!The block has done 98k if its the same engine, Im pretty sure its not as when I was taking it out all the plugs had tape and writing on them!Its hard work trying to learn a new engine, if it was a scooby I wouldnt need to ask all these silly questions! Link to post Share on other sites
matty.vrt 120 Posted March 28, 2010 Report Share Posted March 28, 2010 personaly i think you could bore it out to 83mm practicaly a 3 ltr and not have to worry about the block cracking as engines such as the i5 20v motor have ran upto 1200 bhp and the gap between the bores in 10 times skinnier. Link to post Share on other sites
Phat VR6 3 Posted March 28, 2010 Report Share Posted March 28, 2010 ^^^ you probably would get away with 83mm but it would be safer to keep to 82mm, you get the benefit of fresh bores as well over having drop ins.tbf you would probably be better of with a gt40 if your aiming 700+ and a little head work with make it easier.uprated rods are definitely needed along with 630cc injectors. built 02m and it would be pointless without 4 wheel drive going to be one high spec car :-d im quite jealous Link to post Share on other sites
UnitedMotorsport 55 Posted March 28, 2010 Report Share Posted March 28, 2010 83mm isnt a problem atall. We have tuned to passed 500whp with this bore diameter. Link to post Share on other sites
Scaley 0 Posted March 28, 2010 Author Report Share Posted March 28, 2010 83mm isnt a problem atall. We have tuned to passed 500whp with this bore diameter.Cool, would I be able to get all bits from you i.e pistons, rods,cams,valves,turbo?Also what do you think of the omex 720 ecu for VR6 applications?Cheers Mike Link to post Share on other sites
bungy 2 Posted March 28, 2010 Report Share Posted March 28, 2010 Hasn't Paul just built a 3.0 VR6? Link to post Share on other sites
matty.vrt 120 Posted March 28, 2010 Report Share Posted March 28, 2010 allot of the ford guys use omex never herd any reviews tho good or bad, sp turbo use dta with some impressive results, also 034 motorsports do some nice bits of kit and they have lots of gt35 base maps to choose from using different boost levels. Link to post Share on other sites
Phat VR6 3 Posted March 29, 2010 Report Share Posted March 29, 2010 if your pushing 35 psi though a gt40 is the extra 100cc of the 3.0l really going to be of much benefit.surly it would be more sensible to keep the walls a bit thicker . your not really going to loose much power.thats why people who build high power 24vs use R32 head on a 2.8 block (24v block) they get the flow of the 32 head but the added strength of the thicker walled block Link to post Share on other sites
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