Anyone modifying biturbo v6 engines ?

[alpa]

Hi,
I wonder if there is anyone over there who did or wants to/does modify/improve an 18v or 24v biturbo v6 engine (or maybe v8 biT even though there are few major differences with the 3200GT v8) ?
I'm not talking about "I bought a 224 my neighbor drives a late M3 I wanna win red light runs please tell me what to buy". Answer: buy a M5.
I'm talking about opening the engine and looking for everything that can be improved, searching for solutions, discovering interesting things, spending money and time.
Most of people open to repair/replace and don't care about why and how all that works.

I know it's a very high secret domain and people "who know" don't speak. I guess because they are afraid to loose their business (like if describing cooking recipes was a danger for good chefs).
Even though those who design 24hdM and F1 engines say that there are no big secrets any more about performance IC engines and that the unknown is elsewhere. I guess motor engineers laugh a lot reading most of the discussions on forums. Or may be they don't read them to save time.

On the web there are many technical discussions about how to prep BMW, Alfa, Honda, Peugeot and most of other brands' engines. And nothing about Maserati biturbo. While today these cars are not expensive and they were well designed.

We've had this discussion:

https://www.sportsmaserati.com/index.php?threads/piston-weights.33582/

however with no outcome.

Well may be it's pointless to ask these questions: nobody cares about the engine, the painting and rims are much more important ?
Or may be I'm an old idiot: I should create a FB account, seems like real life is there ?

 

[A.S. Motorsport]

We're busy with a number of projects, and actually building a Ghibli Cup now in the shop.
For example right now going into the Cup here:

• Plug in ecu conversion to Haltech ECU
• EV6 injector conversion on this car, I am working on EV14 injectors too
• Sensor upgrade kit (prototype pictures on our facebook or insta)
• Turbo refresh and upgrade service, (we're mid way trough this portion)

 

[alpa]

Even if a good engine management is essential to me it's unrelated to the mods of the engine itself.
You'd certainly have made your adaptation even if the engines were perfect, right ?
Let's make a separate thread for the management.

In fact your programmable system will expose even more the limits and weaknesses of the engines, as people will be able to increase boost or RPM, change turbos, ... and expect improvements. That won't come as expected.

For engines with ignition distributor I went a different route: I'm using my own ignition firmware (that has a built-in diag system, I've been selling it for more than 3 years) so I can change anything I want, and I disassembled and improved the injection ECU so I can map it as well. It's an easier configuration than the two identical ECUs on static ignition engines that must be mapped in the same time.

 

[alpa]

BTW, are you using stock (recent tinned version) thrust bearings on the Cup ? Is it a 2.0 Cup ?
How was the old thrust bearing and what's the mileage ?

Do you know the big-end clearance with a brand new big-end bearing ? Are you using the Maserati or Audi bearings ?

 

[A.S. Motorsport]

Well a good accurately running engine is most critical to keeping these cars on the road and reducing diagnosis cost, this is a large part of why we're making such conversions.
That will allow in first stage to have for example a 24V run as safe and health as possible and that off-course will induce more volumetric efficiency = power and torque

Second stage is getting more out of the engine, any Maserati engine is actually rather beefy they have to be with the limited "control" versus the amount of power potential.
I'd say the stock turbo's are going to limit the envelope of performance on the engines. as that's a very expensive step.
Side note, I wish i had designed the Cup EVO style manifolds beforehand, this was/is a real pain in the Cup car we're building having to combine a setup to replace the OE turbos.

As for distributor versions i've got customers wanting to switch to coil on plug.
Which we've already planned out how to simply upgrade those cars, that said i haven't yet designed a direct swap modern ignition coil to replace the QP4/32GT style coil (which require igniter module, which i'd want to eliminate)
I intend to dummy install Bosch coils and match something up, pretty much going to boil down to a GranTurismo style push in Bosch coil or a bolted 4200GT style Eldor coil (I'd use DENSO if that way is needed)

Engine internals
On the Cup car we're just refreshing the engine won't be opened it's very very low miles, as for bearings and the thrust washers this is something i'll look into in my next engine build in which we have some time.
Previously we used our inventory of Maserati bearings, gaskets and just had pistons made.

At this point we're running rather low in OE bearings so it's going to be the natural evolution here to fix that issue upgrading it.

 

[goranw]

Coils is not an issue. You can use the longest VAG coils, several manufacturers Bosch, Beru and more.

 

[A.S. Motorsport]

Coils is not an issue. You can use the longest VAG coils, several manufacturers Bosch, Beru and more.View attachment 96508

My plan too, I've
done such conversion on NSX before, and i have inventory here of the Ferrari/Maserati ones so i can match a length it's all the same besides the length

 

[del mar 2]

Impressive work here.

I guess the rarity and cost of parts has put people off "tinkering" with these cars. The "infamous" Blue Cup broke a rod (i think) when they removed the rev limiter in the pursuit of more power.

A more modern ECU presumably allows a lot more scope, and offers a better replacement part when the originals die, but is beyond the abilities of the average diyer.

 

[A.S. Motorsport]

Most certainly, we can then convert over to for example firstly 3200GT spec parts (we've done some testing on V8 and are now machining V6 parts to do so)
It would also greatly simplify diagnostics as you'd now be able to get a full read out with DTC's.

A better running more accurately controlled engine will also have benefits in running costs and wear & tear.

 

[alpa]

Just discovered this

https://www.pureperformancemotorsport.com/maserati.html

Conrods for 2.0/2.5 18v and all 2.8 engines.
I guess someone bought them. However I think it's a bad choice to pay $1200 for such good conrods and to use them with pistons of stock dimensions. I would make rods longer and design shorter pistons.
Now I'd like to understand the crank balancing rules: how these 550gr rods are supposed to be used in place of the stock 640gr rods.

 

[A.S. Motorsport]

to be honest, connecting rods, pistons and sleeves is super straight forward pieces and i haven't seen accurate data of mechanical failures in the later cars (coil pack cars) (cracked piston ring land due to boost, failing rod bolts, cracked sleeves)
First of all i'd say upgrade to GT/3200GT turbo dimensions and you'll be going towards a good 400HP worth of air, dealing with that is the first step

 

[alpa]

What' the problem with turbos ? Modena sells 450hp 3200GT preps with stock turbos.
I claim V6 are limited by the heads. We have a post about a 370hp limit, Modena sells up to 350hp with stock V6 turbos and heads. Heads are the same on 2.0 and 2.8 24v.

The stock hardware is strong. However a 2.8 v6 turbo engine that produces 285hp it's ridiculous, and even 2.0 300hp isn't that much. Fortunately there are no failures, the opposite would be a shame (given the original price of these cars). But if someone wants to get reliable 450-500hp from a V6 some parts must be redesigned. The GT/3200 conrod pins are too small (20mm), the older conrods are too short so pistons are excessively tall (and thus heavy).

BTW the thread is about V6. And PurePerf rods are for V6. Not the same as in 3200GT.
I've never been interested in this v8 because to me this engine is overkill or just to show off. 3.2 8cyl turbo to make 320hp. 100hp/L, 40hp per piston for what price. The 3200gt engine is a non sense. F1 ultra high compression heads with diesel pistons, simple (not double) valve springs, iron cast !!! valve guides LOL, three groove valve lockers. Looks like Ferrari had a warehouse full of spare parts.

 

[goranw]

I have "some" experience, the most weaken part of my engine was the sleeves its a 3200 engine, maybe it was a coincidence, maybe it was predamaged ? who knows? The sleeve come from a 3200 with 32000 km.
I would also say all internal parts of 3200 and V6, at least from Ghibli era, is really good.
I and several of my really experienced friends here, Turbo guys and very experienced engine builders are of the meaning the turbos are to small for huge HP. Just look at what the guys with 700 - 1000HP has for turbos on their engines. I myself have been able to get 666 HP with E85 out of a very modified 3200 engine in a Ghibli, BUT standard unmodified internals. The part that broke, on the street, at high boost, high ignition and high temperature was one of the sleeves. I could probably have hit the 700 HP wall but I was scared to destroy the engine again so I stopped at 666. yes I have modified turbos, it is IHI std Maserai housings but completely custom built inside. And, it is very expensive to update Maserati engines there is nothing to buy of the shelf. So I stay at this level.
To my opinion, and it is my opinion and experience, not in any way scientifically proven, investing money in changing the engines internals is waist of money (a lot of money) if you dont completely rebuild the turbos, preferably change to new bigger turbos. Which again with needed rebuild of several parts will cost a huge lot of money. Of course conrods, pistons, sleeves camshafts, all can be ordered to your own spec but sum up the costs and it will be very huge, and the plug in the exhaust will still be there.
I have had different Maserati Biturbos since 1988 and I have always tuned them since then, always aiming as much HP as possible, so I am not completely new in the Maserati world.

 

[alpa]

I've never worked on the 3200 engine. But I own some parts: heads, oil pump, flywheel, turbos, a random set of cabin and mechanical parts that I bought few years ago. Guess why was it sold ? The guy had acquired a car smashed by a tree just for liners ... I have the bill, not cheap. His less than 100k km 3200GT had toasted liners. Later I've heard two other stories like that.
Weak liners are not rare in industry. For example 350z had a notorious problem with liners past 100k km. Probably because liners is a REALLY expensive part. So they all try to save on that.

I'm not surprised the liner on your picture seized at the weakest point. People would tell you that these liners should be redesigned to have much thicker shoulders: good for robustness, good for the head gasket (allows to use copper rings). Accross V6 engines I prefer the 2.5 liners: they have 8mm walls, 2.8 ones are 6mm thick (they are totally different and weaker).

The other frequent problem on 3200GT is thrust bearings: a lot of 3200gt have a huge lateral play and they end up toasted. I know one 3200gt that ran with overlapped thrust bearings: engine impossible to rotate manually. The same less frequent problem is known on GT and QP4 V6/V8. All with the Getrag gearboxes. I have a theory about that and I've ordered modified sets of thrust bearings because I don't like the late models of the bearings. Initially (before the Ferrari era) they were wider and bi-metal, but then Ferrari switched to an equivalent part, I think it's the same as Glyco A265/4 or A176/4.

I don't know (and I'm not really interested in knowing) what's limiting the 3200gt engine. 660hp is a good number, it's more than 200hp/L. 80hp per piston with 20mm piston pins is probably close to the limit, especially without oil squirters. 22mm should be enough. 3200gt heads should obviously flow very well. I think the weird diesel style pistons are a source of wasted kW. At least the V8 is not over-square so it gets more torque on the crank and has certainly a better thermal efficiency.

I don't agree: you may want to change internals and keep stock turbos. I'm doing lots of mods in the 2.8 18v engine because there are lots of varius (including maintainance) problems to fix and because I want a better thermal efficiency. This starts with a higher CR (7.4:1 was good for carbs), some work on the heads and parts alignment. Everything that Maserati was financially unable to improve (even though biturbo cars and engines have not stopped being improved through the years until 2000). With stock turbos I expect to get at least 320hp and 500Nm. If I get 500Nm from 2500 rpm up to 7000 rpm the car (1250kg stock) will be a rocket. This V6 is a piece of art it just needs to be properly finished. As I've already said I prefer the 18v heads for their cost, size, weight and performance. The stock 24v heads are overkill because valves are too small and increasing their size is complicated (Modena do that past 350hp), the valves have 3 groove locks, cams don't lift enough (18v cams lift more the smaller valves), the cam chains cost today 300e a piece (and last 100k km), the heads take too much room under the hood.

 

[alpa]

To my opinion, and it is my opinion and experience, not in any way scientifically proven, investing money in changing the engines internals is waist of money (a lot of money) if you dont completely rebuild the turbos, preferably change to new bigger turbos. Which again with needed rebuild of several parts will cost a huge lot of money. Of course conrods, pistons, sleeves camshafts, all can be ordered to your own spec but sum up the costs and it will be very huge, and the plug in the exhaust will still be there.

Rebuilding an engine is often motivated by the need to rebuild it: it's worn, it has a problem, it's not performing well. You open and you check what's to be replaced. You see that turbos are OK but pistons, liners, bearings, valve guides, valves are worn. That heads are corroded (because people use these cars once every 3 months), pistons have 15gr of mismatch, guides and bearings are 0.02mm outside the spec, the whole engine previously rebuilt with old gaskets and seals secured with the seal in tube. Well may also find a proud semi-15w40 sticker under the hood, 1L of fuel in 5L of the drained oil, 5mm of mud in the oil pan, the whole list would be long.
What you are supposed to do ? You are supposed to replace worn parts (often all the listed is worn), and also to check whether valve springs are in the spec, in theory replace valve locks.
You probably know the prices of new Maserati parts. Did you compare them with the prices of modern custom made and competition parts ? I'm ordering custom engine bearing and gaskets, guides, pistons (next time conrods), and I'm using competition (or OEM from other brands) retainers, springs, valves. Because all that is same price or even cheaper than "OEM" Maserati parts (which are often poor refabrications and sometimes FIAT OEM matches). Is 300e per piston huge ? 11e per bronze guide (3200GT stock guide are cast iron), 300-350e per set of bearings, 5-10e per gasket. If these prices are huge then I'd like to know your sources. The only part that is really expensive in custom is a liner. But OEM are out of stock. So you rebore them and ... well you order custom pistons.

 

[del mar 2]

Reading all of this....

How do i get another 50 - 100bhp out of my 2 litre Cup engine ?

 

[alpa]

If you are kidding then swap for a 3200 v8
If you are serious then see my answers in your thread about your GT prep.

 

[alpa]

I've realized that the 3200 sleeves are semi-wet: wet on 35mm, then dry all the way down. This is the same architecture as in the classic Maserati v8 which was known to have weak sleeves. The two reasons seemed to be: first the fact that the dry part is subject to a higher aluminum thermal expansion that creates a warpage on the sleeve. The second is that different thermal expansions would leave a space when the engine is hot: thus poor thermal conductivity and water vapors entering this space (unless every sleeve was carefully machined to match the bore in the block).

I have "some" experience, the most weaken part of my engine was the sleeves its a 3200 engine, maybe it was a coincidence, maybe it was predamaged ? who knows? The sleeve come from a 3200 with 32000 km.
I would also say all internal parts of 3200 and V6, at least from Ghibli era, is really good.


View attachment 96683

 

[henris42]

Well for my rebuild the reason was I had a blown exhaust valve.

I'd loved to make custom internals to have more bore and compression, but as the parts availability and delivery time is what it is, it will have to wait. I guess I have to get myself a second engine to do a better one. I got from ebay set of 2500 wet sleeves that look good, would need custom pistons though. If any of you have good sources for such custom pistons, please share!

For now its just the normal 2.24 with rebuilt heads and turbos with new internals like billet compressors. Currently my main project is doing all the electrics for megasquirt3+flexfuel, also I put a new big vacuum pump which will enable stop&go functionality in the near future (old one was bust). Stop & Go means the brake vacuum has to be kept to I rerouted the vacuum. I'll probably electrify the steering pump as well, I got a nice Volvo/TRW unit.

.. One season for steering electrics is the horrible belt arrangement, one of worst I've ever seen. I've been seriously thinking a kit to make it auto tightened.

//HS

 

[alpa]

I did not get why you need a bigger vacuum pump. Do you want to be able to brake many times with a shut engine ?
The first thing I do on all my biturbo is to disconnect the vacuum pump, it drains the battery when the engine is stopped.
I'm planing to move the steering pump on the other side of the engine, above the alternator. Electric steering pumps are huge and consume lots of electric power.
Today custom parts are not expensive, but you need time to find providers, specify the parts and so on.