[Mk2] [Turbo] Maximum Rev Limit

[Turbonoz]

Has anyone come across any issues with an 8k+ rev limit such as valve float or, God forbid, an escaped con-rod? Standard bottom end & valve train components. Has anyone gone higher?

I've ran it for a long time at 7300, and had a couple of runs at 7600 & 7800 RPM up the strip. With my set-up, I need as high a rev limit as possible, but obviously not at the expense of a broken engine

[alanmr2turbo]

like everything in life RED = Danger or thats what i've always thought.

So i'd imagine if you keep going into the red with your standard internals will pop through the side of block after a while.

[Turbonoz]

I have no doubt the engine will die one day, as all engines do. After all, it is high-mileage & bone stock (apart from a metal head gasket) with a T78 strapped to the side of it.

But, as with most drag/track/drift cars, driving hard is a requisite

Basically, what I'm looking for is someone willing to share experience and to say:

1. Valve float at xxxx RPM
2. Con-rod bids for freedom at xxxx RPM

or, failing that:

3. You're on your own mate, let us know how it goes

[alanmr2turbo]

the simple answer is the high the revs and the longer you keep using the higher revs the sooner your engine will die dramatically. You could be ok for 100's of runs (doubtful) or it could pop on your next run.

People who use their cars for drag racing, build the cars for drag racing and even then they got pop

So my answer is............ you're on your own

[Turbonoz]

Sigh

I know it may well die, but that's not what I'm interested in and nothing to do with the topic really. Everything dies in the end.

I'm not looking for a simple answer that it will die, I want to know of specific issues with high rev limits on a stock 3SGTE, ideally from those with empirical evidence to back it up. Anything to help me out as I continue to tune the car to the limits without it going pop.

Cheers

[alanmr2turbo]

Well here's my evidence

I stripped a car that had done high revs. Con rod went through the back of block (big hole by turbo), oil over the road, forged piston was in many bits in the bottom of the sump.

Now that was at around 7500rpm when he said it went bang.

I guess he should have uprated his con rods and bolts as well
I'm sure i have some photos of it somewhere, i'll post them up if i can find them.

Now you asked about going higher than 8k on standard internals. I would prob give you an 8th of a mile before it showers the crowd with blue smoke and bits of engine.

I'm not sure what answer you're looking for as there is only one answer and that is above.

Unless you want to here "you'll be ok, it'll use more than normal oil and may have slightly higher water temps".

[Turbonoz]

No mate, try not to be sarky. The first 3 lines of that post is what I'm after.

So, con-rod around 7500rpm

No need for pics, but spec list will be useful if possible.

Cheers

[Turbonoz]

Plenty stateside are saying 8000 RPM before valve-float, which would go against what you're saying, but it's all useful.

I once put a rod through the block in an old Escort MK3. Somewhere around 3000rpm

[alanmr2turbo]

Spec of engine was forged pistons, standard rods, standard bolts with stage 2 CT26 i cant remember what boost he was running though but wasn't mega high

The engine was built by a trader on here and lasted less than 1 year. It could have been the engine build itself as in that year it had to be stripped down rebuilt twice due to faults.

But build the engine right and yes it'll rev to and above 8k safely

[Turbonoz]

Spec of engine was forged pistons, standard rods, standard bolts with stage 2 CT26 i cant remember what boost he was running though but wasn't mega high

The engine was built by a trader on here and lasted less than 1 year. It could have been the engine build itself as in that year it had to be stripped down rebuilt twice due to faults.

But build the engine right and yes it'll rev to and above 8k safely

Ahh, in all fairness mate it sounds like it was doomed from the get-go!

[greeny]

It should be the stock rod bolts that'll cause you problems first at higher revs.

If it was me I wouldn't want to take it above 7.5k on stock bottom end.

As for valve float, I've no idea when it'l become a problem.

[planted1]

Trouble is when an engine is built its only going to be as good as the owners wallet,what you can afford is what your builder will do,
just take a look at Bob Hattons build and you will see what i mean.
Arp fasteners,standard rods should be ok,
in the case of rev1 or 2 mebbe attention to shim buckets being changed to under bucket,and a lightened valvetrain would be good.
Keep the harmonic balancer with its rubber vibration absorber,
and allthough some say the crank from factory is fine,i had mine balanced
and saw for myself the material which had to be removed before it was
what my engine builder would call balanced.
It will rev to 8000 and hold it all day he says,and i have no reason to doubt him.........still......i dont think ill be doing that

[Peter Gidden]

High RPM not always a necessity for big power. Cam choice was a big influence on RPM with this engine we built.

[Turbonoz]

It should be the stock rod bolts that'll cause you problems first at higher revs.

If it was me I wouldn't want to take it above 7.5k on stock bottom end.

As for valve float, I've no idea when it'l become a problem.

I've got no choice, I'll be forever stuck in the 12s with a 7.5k limit 'cos the turbo is too damn big

[Turbonoz]

High RPM not always a necessity for big power. Cam choice was a big influence on RPM with this engine we built.

Nice

Once I've done all I can do with the standard unopened engine, I will be looking toward cams, it's really struggling on the stock ones. I've set my sights at getting into the 11s on a completely stock 3SGTE & 'box first, but I'd be surprised if it does it tbh. The only options I have are more boost, refined mapping, highest possible rev limit, and lastly but not leastly, drag skills

[T.F.S.]

Because like you I am on the stock engine I took the decision of reducing the RPM limit...stock is 7200rpm IIRC? But mine is limited to 7000rpm....my GT3071R runs out of legs at 7K anyway so why go further.

Do you know how much power your car is making at the present boost level? (1.8bar IIRC?)

[bobhatton]

My understanding is that max power is around 6250 rpm on a stock engine so there no point in going higher.
The problem you have is the wrong turbo for the stock engine

[Turbonoz]

Because like you I am on the stock engine I took the decision of reducing the RPM limit...stock is 7200rpm IIRC? But mine is limited to 7000rpm....my GT3071R runs out of legs at 7K anyway so why go further.

Do you know how much power your car is making at the present boost level? (1.8bar IIRC?)

I'll hopefully get it on the rollers once I've gone as far as possible with it in its current spec. The T78 is too big, no doubt about it, but it screams well and the car pulls & pulls to 7800prm (highest I've dared take it so far).

My understanding is that max power is around 6250 rpm on a stock engine so there no point in going higher.
The problem you have is the wrong turbo for the stock engine

The max power will depend on the turbo, surely? Yes, it's too big for an everyday car, but it's doing well on the strip and I like big lazy turbos, as I've had great results in the past. I have a GT3582R and a modified GT4088R sitting around but also have other projects on the go, so the 3SGTE is stuck with the T78 for now.

[Al-sw20]

Do you monitor oil pressure at those high revs? The only real issue I can see would be the oil pump not being able to keep up. If you are keeping the det at bay, rev it to 8000rpm and monitor the oil pressure.

[bobhatton]

It is the cams that will determine where your max power is, nothing to do with size of turbo or boost.