- 1 Post
- 7 Comments
1·1 year agoStory Time! 10 years ago I worked at a consulting company on the 4 cylinder turbo now found in Jeep products. And ~9 years I got I worked on the Cadillac CT6-V Blackwing (the DOHC V8, limited production, although it wasn’t originally planned to be that low of volumes).
On the Jeep GMET4 engine we had big budgets. They were going to make millions of these things. We had multiple turbo suppliers lining up for the business, and had budget to get a ton of turbo prototypes to try out and compare for best torque curve, compressor surge, spool, etc.
On the Cadillac CT6-V Blackwing, we didn’t have jack for budget or resources. The first set of turbos we had had a number of problems with the design such as the wastegates needing to control boost better. The Cadillac vehicles cost way more money than a lease special Jeep. The volume were so low though that no suppliers were interested in doing the job. We only got the supplier to agree to do the bare minimum of work because they were strong armed by having other higher volume business with GM.
The lesson is, small volume vehicles actually don’t get a lot of focus. You usually can’t make any money off of it as a supplier, and suppliers do a large amount of the work. So don’t be surprised that so much of a Pagani is reused or lightly massaged existing parts. McLaren was using a Nissan engine for years.
The last car I saw with that in the states was my college roommate’s base model 1996 Civic CX hatchback with manual steering
Typical German car nickel and diming for every feature.
Head design is a big one. Look at a fox body Mustang 5.0 and a current 5.0 ; DOHC, variable cam phasing, and direct injection. Put sophisticated intake manifolds on there (which go back to the 80s as a widely available tech) and you get a lot more power, when you consider things like the higher compression ratios the tech enables.
US market 300zx turbo was down on power in 1996 and then no longer sold.
Not all sequential turbocharger systems from the 80s and 90s worked the same way. For example the Porsche 959, Supra, and Rx-7 all used different types of valves to control the exhaust flow. Fitment and packaging were a big constraint. It’s likely that contributed to the finicky nature of the Rx-7s turbo system.
Highly researched article I wrote a long time ago with actual paper citations: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/comparison-rx-7-13b-rew-supra-2jz-gte-sequential-turbos-960727/
Story Time! 10 years ago I worked at a consulting company on the 4 cylinder turbo now found in Jeep products. And ~9 years I got I worked on the Cadillac CT6-V Blackwing (the DOHC V8, limited production, although it wasn’t originally planned to be that low of volumes).
On the Jeep GMET4 engine we had big budgets. They were going to make millions of these things. We had multiple turbo suppliers lining up for the business, and had budget to get a ton of turbo prototypes to try out and compare for best torque curve, compressor surge, spool, etc.
On the Cadillac CT6-V Blackwing, we didn’t have jack for budget or resources. The first set of turbos we had had a number of problems with the design such as the wastegates needing to control boost better. The Cadillac vehicles cost way more money than a lease special Jeep. The volume were so low though that no suppliers were interested in doing the job. We only got the supplier to agree to do the bare minimum of work because they were strong armed by having other higher volume business with GM.
The lesson is, small volume vehicles actually don’t get a lot of focus. You usually can’t make any money off of it as a supplier, and suppliers do a large amount of the work. So don’t be surprised that so much of a Pagani is reused or lightly massaged existing parts. McLaren was using a Nissan engine for years.