Biturbo Spyder 1991 2.8 18v non cat engine upgrade

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Hameng

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I am currently restoring and upgrading a 1991 Maserati Biturbo Spyder 2.8 18V and would appreciate some advice from people with experience building these engines.


The project is being done in two stages. First stage is suspension, brakes and chassis upgrades so the car can safely handle more performance. Second stage will be the engine build, including cooling upgrades.


The car will receive a modern ECU, larger intercooler, upgraded clutch and supporting modifications, but I am still trying to decide the best turbo and engine setup.


My goal is not to build an extreme dyno car, but rather a fast, reliable and usable OEM+ road car with strong acceleration and good drivability. I would like to comfortably exceed 350 hp, with some future headroom beyond that if possible, while avoiding a fully forged engine if realistic.


I have read many different opinions regarding:


  • stock vs hybrid turbos
  • Ghibli vs 3200GT turbos
  • safe boost/power limits
  • engine durability
  • cooling requirements
  • spool characteristics

Some threads mention these engines can handle surprisingly high RPM and power levels, while others recommend a more conservative setup.


I would therefore really appreciate advice from people with real-world experience:


  • What turbo setup works best on the 2.8 18V?
  • What power levels are realistically safe on the stock bottom end?
  • At what point do forged internals become necessary?
  • What cooling upgrades are recommended for this level of power?
  • What combinations have proven to work well on road cars?

The goal is to build the car the way Maserati perhaps would have built it with modern ECU and turbo technology, while keeping the original character of the
 
Did you read engine related discussions here ?

What torque do you want ?
Why do you need 350hp ? I mean did you try to drive this car with 300hp on the road, not on the park place straight line ?
Why an upgraded clutch ?
What do you mean by cooling upgrade ?
Why larger intercoolers for 350hp ?
What is a safe boost ?
What is a high rpm ?
Did you study the chassis and did you do the first stage ?
 
No, to be honest I have not yet read all the engine related discussions here, there is a huge amount of information and I am still trying to learn these engines properly.

The reason I started this thread was exactly to avoid filling the turbo thread with broader project questions and instead get advice from people with real-world experience.


The goal is not a drag car or dyno queen. I am trying to build a balanced OEM+ road car with strong midrange and high speed acceleration, while keeping good drivability and reliability.


350hp is not a fixed number, more a minimum target for what I personally would consider “modern fast” performance in a lightweight Spyder. I am not looking for huge low RPM torque or an aggressive on/off power delivery.

The upgraded clutch is simply because torque will increase significantly with modern ECU and turbo upgrades.

By cooling upgrades I mainly mean improved intercooling and temperature control, not turning the car into a race car.

Regarding safe boost and high RPM, those are exactly the things I am trying to understand better from people who already built these engines successfully.

And yes, suspension, brakes and chassis work are actually stage one of the project before the engine build.
 
Not sure a Biturbo Spyder is the right starting point if you want a modern fast convertible, for me they have always been about the understated style but each to their own.
 
It’s just that the restomode trend have not arrived att Maserati yet apart from the Shamal. If you know what a 911 Singer is you will understand where I am going with my Spyder. Some people love it some hate it. For purists I will keep all parts so it can be restored to original.
 
A question it seems like Maseratinet have stopped manufacturing a front strut brace for the biturbo. Does anyone know if there is a company that provides that part. I tried to get the drawings from Maseratinet but they did not have them. So I guess there will be more tailormade solutions if I can’t find any.
 
Yes, David used modified Brembo brakes, I will use Tarox as will have 17 inch Japan racing wheels, looks like OZ racing but can be made to measure. For suspension he used Passiones but I will use bilenstein. Passione has said they will have the system ready that David got later so I might upgrade to that later, electronically controlled coilovers . That said Passione has a lot of plug and play solutions from their 2021 project car, ranging from intercoolers to a new clutch that can manage 650nm. But thank you for input
 
So you plan to have up to 650nm ? Did you try these cars with 500nm ? Balanced OEM+ road car ? Is that a joke ?
I'm also currius to know what "safe boost" level will be required to get 650nm from these heads.
 
No but given that Passione Birurbo have that plug and play clutch so why not, I will probably not run more than 450NM and 360hp. But yes I know a Spyder totally rebuild with 480hp at 1 bar with 3200GT turbos, clutch and gearbox but still a forged 2L 24v, it’s for sale if you are interested
 
For 450nm the stock 240mm clutch is just fine.
480hp at 1 bar on a 2.0L engine ha-ha, very funny. That's even more than what you can get per liter from a 2JZ that has much bigger valves.
 
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Okay, reason I am having this thread is because I need input from people who really knows this stuff and from seeing your comments I recognise you really know these engines and turbos etc. Do I dare asking you what you would suggest if I want to have 360hp but max 1 bar max 450nm but very reliable with modern ECU. The Spyder was a dream car when I was 16 years old and I have never let give of that car. After modern sport cars etc I found this Spyder that have been in a car collection since 1998 and not being used but as I really would like to be able to use the car I want to modernise it and I also think it deserves some power upgrade, and yes I will keep everything to be able to restore it.

Here is a link to the Spyder with 480hp 620nm

www.biddershighway.com

1987 Maserati Biturbo Spyder - Bidders Highway

Förfinad, genomgången och trimmad Maserati Biturbo Spyder
www.biddershighway.com
 
What you said about the preped car is not what is described in the link at all.

As I've already told you you need to read forum discussions before asking. People did spend their time posting here, their work deserves some effort from your side.
I won't reply to your questions unless you provide numbers or rational arguments. Talks about void are just a waste of my time.
To answer your question: at 1 bar you'll get 450nm but likely not 360hp with stock cams (the only available AFAIK). You'll need a higher boost to get 360hp, probably 1.2 bars. Power = const * torque * rpm. A physics law.
Modern ecu or not does not change much for the power, it's more about management precision and options.
You decided the car deserves a power upgrade but I suggest you to drive such car with 450nm first. If you can't use power it's useless.

Btw stock ecus are reliable. The problem is the absence of the diagnostic. That's what I've worked on for years. But if you have money and time to invest in a modern Ecu then go with that, it's better.
 
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Don't forget these cars had zero power assistance. These aren't modern Goff turbo quatro whatever where the driver is a dead weight indicating the next destination.
 
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