F40 wastegate manipulation

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I would like to ask something about the F40 wategate nut. Wonder if someone have experienced in this manipulation for higher turbo boost, because Ferrari says absolutely not manipulate it...but some F40s seems have manipulate it.
Some stock F40's racing owners seems used this method for fast track sessions with boost 20 psi calibrated (from the 16 psi stock setting) and often it seems used as definitive road wastegate calibration for every day use.

Waiting for opinions or experiences. Thanks.

 

My opinion:
If you have access to a dyno you can run the waste gate up until the Fuel Injectors run out of fuel timing.
If you don't, you can "get away" with a little more boost (2-3 pounds seems reasonable)
But there is no "lack of performance" to need being covered. That is, the F40 is the animal it was designed to be, no steroids necessary.

 

If you are going to tweek boost,please don't do so unless your car is strapped to a dyno and with a Ferrari tech nearby. Post non-cat adjust models seem quite lean on the map under boost, I'm sure people who have done this will be along shortly but I'd advise caution!

 

There are some guys who know what they're doing in this realm. There is a pattern of guys changing the exhaust and then getting into overboost situations with the turbos because the wastegate was not modified accordingly. I am no expert on it but I have talked to a few people who really are and there is consensus on the issue. I would start with a conversation with a real F40 expert and go from there.

 

This is a fairly well known and established mod which was worked out by Michellotto "back in the day"
Since this is a safe and time proven mod which gets you right up to the threshold of requireing straight cut "double truck" tranny gears(650-750?), why in the world would you try a DIY'er mod on a car with a $100k+ DOWN SWING IF IT BLOWS UP?

I'm guessing that you know of the mod which requires internal machine shoop mods of the waste gate, and manipulation of the DUTY CYLE signal which modulates the circuit, as well as vac line boring sizes...theres more...
removal of cats-required due to the heat function change in delta-the rate of the rate of pressure bleed off, leading up to the pop-off circuitry, is what you are paying the money for-this is the "over boost" condition of which you are referring.
FWIW--merely removing a stock muffler will result in hinky-iness in the wastegate programming! resulting in overboosting-particularly when not at full operating oil and water temps...

I suggest that you just pay the money at an established F-40 shop for the trade secrets, almost nobody will just give it up,(I certainly wouldn't due ti the liability exposure) as it took alot of money on the dyno and a few motors to get it right...this is very tightly held info, and you are likely to get most-but almost certainly NOT all of the required data, thus ending in an expensive overhaul....

These cars are, and always have been, cars for experts...I know a Phd from MIT(a professor in theoretical physics actually) who was speechless when shown the partial differential equation used for fuel map calculation timing on a non;linear throttle potentiometer....

be careful as you proceed-FWIW...

 

Absolutely agree with the above post. Don't mess with it, take it to someone who KNOWS the car. I've seen first-hand home made/cheap-end exhaust systems induce wild boost deviations, and as I previously said, the later cars are more sensitive....

 

Having worked on an F40 with after market exhaust and an over boost issue. Take it to someone that knows that car and system. Listen to 355s. Not a problem you want to re-engineer.

 

Thanks for that one......made me laugh.

 

Good advice

Dave Helms rebuilt mine and its working very well. Its a black art with no official public information, so yes you need to see someone who has done it successfully before and kept good notes. There's some parts in there that are made from unobtanium so don't try it at home.

Mine is kicking in right at redline, and its smooth and progressive. Its rather harsh if the car is cold (ie low abmient temp), but that is a well known problem even for a stock car. Changing any of the exhaust or cam timing parameters from stock will give you wastegate headaches for sure.

 

when the back pressure of the factory equipped exhaust is relaxed by removing this exhaust ALONE, will cause a drop in backpressure such that the "spooling up" RATE of the turbos has been altered-this is a time to distance funtion graph in terms of rpm, pressure and volumetric flow....
there is a spring rate co-efficient within the wastegate which has been calibrated to the fuel map as well as a host of other inputs( see the WSM and in the fuel section it gives the partial differential equation of which I referenced earlier), in particular is ambient air temp and pressure AND coolant temperature.
the wastegate in an F-40 is a multi chambered affair such that a "muting'' of activities occurs with the useage of a DUTY cyle(engineers out there will better explain simplistically why the "dumbing down" of the signal and control side circuits is desired)..in these modded apps, typically the modualtion of the spring is affected by modded VACCUUM!
However, this RATE-inherent in the spring-cannot be altered in the inherent temper cured into this spring, therefore, the rate at which boost is bleed OFF prior to full boost is best accomplished via a dis-assembly of the wastegate to first inspect the mebrane(s) integrity, and then to machine some very specific locations to a very specific dimensions, thus altering the bleed off/spooling up rate... differently.
There are additional mods altering specifics of the vac circuit, which are required and needed to complete this mod lest the engine gets scattered, which exceed the scope of this post.

What is CRITICAL to comprehend is that these ARE NOT like the 288 wastegates-nor the early open loop(horizontal 3 pipes for exhaust version F-40), euro-spec version F-40s...THOSE are cave man single spring diaphragm affairs whith a bolt and nut which allows for a "cranking up mthe booist" via a physical spring tensiioning of the wastegates pop-off tensioning value. think 930 turbo Porsche circa 1974/5?

Closed loop cars operate under controls utilising duty cycles....
FWIW...

 

That sounds to me like a code for the spring perch milling and/or chamber modification unless someone has mastered the new spring rates for the WG, which I did learn back in the day but feel nowhere near qualified to mess with.

 

What an exquisitely bad idea to monkey with a brilliant car worth over $500k. To what end? The car is 20+ years old and as great as it is won't run with a GTR or ZR1.

You want a faster car? Get one and enjoy the F40 experience as is.

Now if you simply have relatively unlimited funds, then go for it and keep us posted, but me, it hurts my head to hotrod a car so it can keep up with a Nissan, Dodge, Chevy or even later model Ferrrari.

Got news for you, rust never sleeps and cars just keep getting amazingly faster. I have come to enjoy the vintage experience for all that it is and is not.

 

+100

 

Oh yeah, that car was absolutely fast enough to keep with those cars. No problem with this. My car is non cats Euro spec with tubi fitted. If I wanted a faster F40, I should have kept my old "GT" with engine, turbos, gearbox, brakes and suspension with Michelotto spec.
In fact, for me it is very strange to see the valve manipulated when Michelotto in mine, or in the delivery of other GTs, the valve seems to be untouched. They work mainly on the ECUs and turbo's extent with bigger units in addition to the engine blueprinting. My old car was around 600 hp/480 lbft and very very fast with that valve untouched. Mine was only a question.

 

I suspect that approach is the preferred one for high-performance mods to most turbo-charged engines. I can't speak to the F-40 (or the 288) or to turbo-charged Ferraris in general. But, over in the Lotus world, there has been a tremendous amount of development work over the past few decades aimed at modifications (increased power from the turbo system) for street car use.

And, in general, I think it is fair to say that Lotus (and their aftermarket tuners) have considerably more experience with turbo-charging than does Ferrari (I am not including race-house experts, like Michelotto, doing mods for the track --- as hardly anyone takes street Lotuses racing).

That said, the prevailing techniques for Loutuses are nearly all focused on ECU re-mapping and sensor upgrades. Larger turbos are often fitted as well, but the rest of the mechanical system (including wastegates, exhaust, and associated plumbing) is left pretty much untouched --- sometimes minor changes are made to the intake path to accommodate the increased "breath" from the larger turbos.

And, once the boost increase has hit the mechanical limits of the stock engine internals, if someone wants to go beyond that.....the next step involves the appropriate piston, conrod, and head gasket changes.

So really, other than using larger turbos, nearly all the increased boost is obtained via changes to the electronics, FWIW.

 

Not a "problem" per se, but a function of the computers protecting the engine because established operating temperature parameters have not yet been reached...... a very good thing. It can be a nuisance in the cool weather with the F40's nature of over cooling themselves but, that too is correctable to an extent.

 

By filling your radiator with cement?

That's what I meant, thanks for the clarification! Like I said mine is working very well, and works great for roasting marshmallow's on a cold night!! Folks that have driven behind me at night have seen this blue flame, which is non-existant at idle, a slight glow at 4k RPM, and 2 feet long at WOT!!

 

I agree on everything, in fact Michelotto developed the CSAI N-GT engine that must have parameters as close as possible to the stock unit and every parts of the engine had to be in accordance with championship regulation. No specific engine parts were allowed, so, no appropriate piston, conrod, head gasket and the valve had to be untouched.

I guess that increasing "fixed" boost you have to change all engine internals much closer to LM engine spec. But this is a higher step.

 

Cardboard, as used for decades. Try it on a cool day with dense, humid air.... and cold tires, quite a thrill! It is what I have to do to test drive them on a winter day around these parts.

 

On both the rad and oil cooler or just the one? I got my car to the point where the water temps don't even get halfway on spirited driving on a 90 degree day and now they stay so low when its a 40 degree day. No bueno. Is the 180 degree mark enough for oil temps?

 

Dave knows best but I'm guessing both. I'd love to see that ecu code. Has anybody reverse engineered it?

 

All 3 if you are going to be driving it regular. The concern then is you cant monitor the trans temps. but I dont mind running those a bit higher than normal, better than stone cold. The oil thermostat does a pretty good job on its own but I would rather see the oil temps into the low 200's so a partial block off seems to be required depending on the ambient temps. I had considered making an adjustable Venetian Blind affair like the PF Cab S1's had on the radiator for John's car.... he refused to quit driving it when the weather turned, cant blame him, that was a hoot and these hair dryer cars Love the cool, dense air! Never got around to that because I was so focused on a variable boost design for the track.... that also got shelved about 80% of the way to completion. So much was learned on that car, John has incredible feedback ability and driving talents which made the job easier. The best lesson learned... modifications to the OEM car only slowed it down, blueprinting and optimizing the OEM systems was all that was required.

Yup. It is good as designed BUT there are a few little hidden surprises tucked into the code that can be a lot of fun........ for a Very short time....Serious giggles that WILL find the design limits of other components in the driveline.......NO! Not yet, but I am considering it now that we can contain the combustion pressures and fluids reliably.

 

That's great info, Dave. I am all for improving inefficiencies and correcting a couple of issues in the OEM system but as we talked about earlier, I don't feel any need to make the car faster, more powerful, more violent, etc. It's just great. My earlier point is along the same lines as Keith's: if you want a faster car, buy a faster car. It's not the speed that makes the F40 great; it's the speed combined with the lack of everything else (power steering, TC, power brakes, etc.).

I guess the next question is should we be running two oil weights, one for winter and one for summer? I used 5-40 all year round in the 328 but obviously this is a different beast.

 

So back in the day we had a wonderful customer at LFSC who loved his collection of red cars and we maintained and modified as he desired to go faster each year, sooo, I have a bunch of experience tuning and troubleshooting the F40.

What we did first (c. 1995) was install the only "upgraded"/ "tuned" chips available at the time, which basically added a ton of fuel and manipulated spark a bit (developed originally for the Sultan...) We did this as insurance to run rich and hopefully avoid meltdowns. We then built our own straight pipes and proceeded to learn about turbo "overspooling"/ overrev which spat out the impeller into the exhaust. Ooops!

Then learned of Shelton's exhaust and wastegate system, which was a thing of beauty, worked well. Basically they fabed a really nice slightly attenuated exhaust (cat eliminator) and modified the wastegate to reduce the wastegate spring force, allowing earlier pressure bleed, avoiding overboost while simultaneously improving power/ response.

I have some data I'll post later...

Best,
Rob

 

Reading all that was said about upsetting the fine balance when fiddling with the waste gate
screw, it makes me wonder what happens when cats are removed thus reducing exhaust back pressure? What if the whole exhaust is changed for a more free flowing system like the common Tubi mod?