Big turbo, little turbo and engine capabilities

[JamieP]

As far as i read it Tony is saying anything above a stock rev limit is your risk to take and not your mappers, you are not an engine builder and wont know the answers to his questions, all you have done is given a stock engine a refresh with some new bearings/bolts, myself id take the risk and rev the nuts off it as its not a big money engine, see how far you can push it and in the mean time build up a well speced short block for when the worst happens:D

 

was typing exactly the same, beat me to it

 

[Rob_Mitchell]

As far as i read it Tony is saying anything above a stock rev limit is your risk to take and not your mappers, you are not an engine builder and wont know the answers to his questions, all you have done is given a stock engine a refresh with some new bearings/bolts, myself id take the risk and rev the nuts off it as its not a big money engine, see how far you can push it and in the mean time build up a well speced short block for when the worst happens:D

 

classic . if it blows it blows no worrys

[Paul Whiffin]

As far as i read it Tony is saying anything above a stock rev limit is your risk to take and not your mappers, you are not an engine builder and wont know the answers to his questions, all you have done is given a stock engine a refresh with some new bearings/bolts, myself id take the risk and rev the nuts off it as its not a big money engine, see how far you can push it and in the mean time build up a well speced short block for when the worst happens:D

 

 

 

 

There are other bits that can be affected though, dont forget the turbo which may need a rebuild if bits of your engine have gone through it, plus you'll need to change your oil cooler to. All adds up. I'm with you though, turn up and go for it!

[hodge]

As far as i read it Tony is saying anything above a stock rev limit is your risk to take and not your mappers, you are not an engine builder and wont know the answers to his questions, all you have done is given a stock engine a refresh with some new bearings/bolts, myself id take the risk and rev the nuts off it as its not a big money engine, see how far you can push it and in the mean time build up a well speced short block for when the worst happens:D

 

 

 

 

There are other bits that can be affected though, dont forget the turbo which may need a rebuild if bits of your engine have gone through it, plus you'll need to change your oil cooler to. All adds up. I'm with you though, turn up and go for it!

 

 

My intention is to go 3.4 in a year or so. So hopefully the engine will hold together until then.

[Bailey.]

Turn it up and if it blows it blows! Hellow 3.4. I'm going to go to 7.5k on my stock block with intentions of running it till she blows!! Then upgrade to a forged motor at a later date!

[TLicense]

These are stock robs and pistons Tony. I replaced them back into the engine after I stripped it. The only updated parts I used were all bolts/studs were replaced with ARP's an bearings were replaced ACL race bearings. I refitted the rods and pistons because everything was still in perfect order and the bores were still perfectly round no ovality what so ever. Everything was coated with engine assembly lub as I put it all together, all gaskets, seals and pumps were brand new also.

 

Whether you used stock rods and pistons or not, the process is pretty much the same. As you're just re-using the existing parts I imagine you've not had anything balanced? Not really a problem, but having everything in balance gives the bearings a much easier time of things. For instance if the mass of the pistons is just 1 gramme out of balance, that would put 17 N of load on the bearings (just under 2 Kg's) at a stock rev limit of 7200 rpm. Basically like having a bag of sugar eccentrically loading your main bearings.

 

Anyway, concentrating on your assembly, how did you do up the rod bolts? Did you use a torque wrench or a bolt stretch gauge? I've not used ARP rod bolts before, but I imagine they give you a reference max torque and a bolt stretch min and max to aim for.

Generally, forget about the torque, as actually measuring it is a minefield in it's own right. (Most torque wrenches will have a tolerance of +/- 25 - 30%, even a flash digital one is probably around 10 - 15% at absolute best). Just keep the value in mind so you're not exceeding it.

Bolt stretch is the thing to go for, (within reason, as it's possible to look exactly at the stress induced in the threads of the bolt with some very trick bits of kit) but whether you go for the bottom end of the tolerance or the top end can also make a big difference. I specifically tailor the exact bolt stretch I aim for (to within tenths of a thou) for a given assembly mass to ensure that the assembly is as strong as possible. This enables you to maximise the potential revs that the engine can take. Feel free to pm me if you'd like to discuss things in a bit more detail.

 

It's for all these reasons as Jamie quite rightly mentions that the rev limit has to be the responsibility of the engine builder.

[Luxluc]

Turn it up and if it blows it blows! Hellow 3.4. I'm going to go to 7.5k on my stock block with intentions of running it till she blows!! Then upgrade to a forged motor at a later date!

 

+1 here.

 

Aiming for 720bhp next spring ... and then start ideas on the forged route.

 

Paul : I will probably ask you to build me an engine during my stay in Afghanistan

[Nic]

On a Supra for everyday use, I'd chose a professionally rebuilt engine which is then set up to be fast and reliable, not some highly strung setup to eek out the last drop of hp available.

 

No money was spared on part choice on mine, the engine was rebuilt and I could have probably gotten another 50+hp out of mine by upping the rev limit, upping the boost and having the mapping more aggressively set, but I chose not to, for me it was more important to have a fast car that i could be confident in it's reliability.

 

If I was a mapper and I was faced with a Supra that was on an opened original engine and had had a turbo kit. etc. bolted onto it and the customer was excited about upping the rev limit and running as much boost as possible, I think I''d walk away and not take the risk.

Edited November 13, 2010 by Nic (see edit history)

[JamieP]

On a Supra for everyday use, I'd chose a professionally rebuilt engine which is then set up to be fast and reliable, not some highly strung setup to eek out the last drop of hp available.

 

No money was spared on part choice on mine, the engine was rebuilt and I could have probably gotten another 50+hp out of mine by upping the rev limit, upping the boost and having the mapping more aggressively set, but I chose not to, for me it was more important to have a fast car that i could be confident in it's reliability.

 

If I was a mapper and I was faced with a Supra that was on an opened original engine and had had a turbo kit. etc. bolted onto it and the customer was excited about upping the rev limit and running as much boost as possible, I think I''d walk away and not take the risk.

 

I could be wrong but i dont think Hodge is planning on using his car as a daily driver.

 

In a perfect world so would everyone have pro built engine but hodge is on a budget and wants the car on the road as far as i read it.

 

Mapping is the customers risk, not the mappers.

Edited November 13, 2010 by JamieP (see edit history)

[tooquicktostop]

If I was to build a single again I would start with a well looked after (great service history) stock block that has never been opened, I would not go down the built route again, I have spent well over 40K having engines built on 2 of my cars, seeing how well the stock block performs and considering I only made high 500's/low 600's BHP with the Supra it was not worth it

 

We have seen so many built engines have issues

[hodge]

Thanks for all the input guys. Seems the engine is already built and in the car I'm not going to let it concern mate. If I start worrying about it I'll just end up pulling it out again and start checking everything. I built/refreshed the engine to the best of my ability and was as thourgh as I could be. All I can say is, if it blows it blows.

 

I havnt got a budget for the car as such, And when it's done it's done but ideally I'd like it finished by the show season next year so around May time is what I'm aiming for.

 

 

Tony, that's was a really interesting read mate. I wasn't aware about torque wrenches being so inacutate, I've been in engineering for years and and it never crossed my mind. There's a lot of factors in engine building I've read in your posts that I wasn't aware of either. At 1 point I did consider building a forged block but decided to wait for a couple of years and go 3.4. After reading your post I'm glad I did. My only issue with having an engine built is trust. No disrespect to anyone intended but I've yet to find someone I've dealt with that impresses me with the exception of Ryan. Who I'd trust working on my car anytime. Locally though there's no-one I trust to with my car to to MY standard.

Tony and Jamie are right I'm no engine builder but I'll need to find someone somewhere to do it, unless I spend hours, days, weeks maybe years learning how to do it.

[jagman]

I would not use a 3.4 stroker it is far more fail likely than stock !!

[hodge]

I would not use a 3.4 stroker it is far more fail likely than stock !!

 

Why.

[Nic]

If I was to build a single again I would start with a well looked after (great service history) stock block that has never been opened, I would not go down the built route again, I have spent well over 40K having engines built on 2 of my cars, seeing how well the stock block performs and considering I only made high 500's/low 600's BHP with the Supra it was not worth it

 

We have seen so many built engines have issues

 

The engine I acquired was of unknown mileage and unknown condition - used 2JZGTE's in HK are very rare so I was lucky to find it. Before going ahead with the single build i wanted to ensure that the engine was in perfect working order, so it was opened, cleaned, tolerances checked and all bearings, seals, oil pump, gaskets, etc. change for brand new OEM items - the OEM parts were more than up to the power that I would be running. Parts wise it wasn't that expensive, labour was more expensive, but worth it for peace of mind and reliability.

[hodge]

I'm pleased I opened mine up to be honest. It was a mess inside. The head ports were full of carbon and also on top of the pistons and around the top of the bores. The engines like new inside now.

[jagman]

Why.

As an Idea Ford/GM are talking about a new joint engine development , cost 1 billion dollars , ONE BILLION !!!

This is the sort of budget OEM uses .

The stock crank would have been developed by teams of people , and every aspect catered for.

Things like harmonics would have been tested and designed for , more testing and development in any small aspect than all the aftermarket put together multiplied by 100.

Toyota can run cranks to 10000 rpm for hours on end until failure , then analyse a pile of broken cranks , adjust harmonics,damper, crank bend ,oil films,and a host of things .

They are fitted in 100000s of cars covering 100000s of miles .

Changing the stroke almost makes it a different engine , with minimum testing and evaluation,so taking Toyotas base it must be better to improve things like bearings,rod bolts , finer stock balance limits,oil quality etc .

You are starting from an awesome basic design!

All engine parts were designed to work together from the start , that's why stock unopened engines can run 800+ bhp without instant failure! Try nearly 3 x stock output on just about any other engine 15 years old and see what happens...

Toyota got it right , and not by chance

[hodge]

As an Idea Ford/GM are talking about a new joint engine development , cost 1 billion dollars , ONE BILLION !!!

This is the sort of budget OEM uses .

The stock crank would have been developed by teams of people , and every aspect catered for.

Things like harmonics would have been tested and designed for , more testing and development in any small aspect than all the aftermarket put together multiplied by 100.

Toyota can run cranks to 10000 rpm for hours on end until failure , then analyse a pile of broken cranks , adjust harmonics,damper, crank bend ,oil films,and a host of things .

They are fitted in 100000s of cars covering 100000s of miles .

Changing the stroke almost makes it a different engine , with minimum testing and evaluation,so taking Toyotas base it must be better to improve things like bearings,rod bolts , finer stock balance limits,oil quality etc .

You are starting from an awesome basic design!

All engine parts were designed to work together from the start , that's why stock unopened engines can run 800+ bhp without instant failure! Try nearly 3 x stock output on just about any other engine 15 years old and see what happens...

Toyota got it right , and not by chance

 

But you could say that about every mod out there on the market. Why change because stock is best.

[johnny g]

But you could say that about every mod out there on the market. Why change because stock is best.

 

I'm just going built head on mine and limiting the boost to what Ryan thinks is sensible. If I do go built, I'll go built 3.0 I think.

[jagman]

But you could say that about every mod out there on the market. Why change because stock is best."

Not every mod , but most, funky coloured cam pulleys , that shear the timing belt , still sell eh!!

Lowering springs still sell,,,,

But there are things like cooler plugs that are beneficial , it's just a case of sorting wheat from chaff,and there is a lot of chaff,,,