Supercharging a 2.7

[Mick_D]

I'm starting to think about the motor. I have a '76 2.7, if I keep it I would like to put a supercharger on it in addition to EFI and a good ESM, etc. Anyone seen a supercharged 2.7 before? How well do they hold up after the usual problem areas are addressed?

[kenikh]

Been a while, but yes. There arent any readily available kits, so youd better be good at fabricating. A Buick roots style SC is a good choice to wake that 2.7 up down low and keep the power in the safe band. You really dont want to exceed 300HP on a mag case. You'd like see 250 HP with the aforementioned SC.

EFI and ECU control of the compressor clutch will be critical in making a motor that runs well and runs reliably. Good luck!

[Mick_D]

My target was for right around 300 hp. I can build a bracket or two and handle a serpentine belt setup, but casting or even welding a new intake might be beyond me. I'd also be running a meth/wter injection system fulltime so that may complicate the ducting but will definitely keep the detonation and heat at bay. Possibly a twin-plug thing too but only for keeping temps down.
Gonna be a long road though. At least another year.

[kenikh]

Twin plug is a given.

[Mick_D]

Thought as much. Block off the distributor and go with all-electronic timing? A twin-plug distributor runs as much as a good ECU does these days!

[kenikh]

^ truth

I run crankfire and coilpacks.

[Mick_D]

I like the coilpack idea. Probably going to use this compressor:
https://whipplesuperchargers.com/index.php?dispatch=products.view&product_id=336
Seems like the smallest package and most efficient.

[Mick_D]

Thought about a Paxton but a centrifugal SC doesn't make sense to me here performance-wise.

[Rodsrsr]

For the 300 hp target, the centrifugal is a perfect fit. Very easy on the gearbox too. People are often so concerned with HP that they forget about the problems the extra HP brings. For a relatively modest goal of 300 HP, (which equates to low boost) I really dont see the need for the added expense of twin plugs. I ran a Paxton unit behind my 3.2 for years and it was awesome. Finally went turbo, which is a game changer, but as I said it comes with additional issues. Finally got the car tuned right after chasing down the appropriate MAF but still need to be careful with the 915 gearbox. I've run 8 to 10 psi BTW, single plug no problem.

[Mick_D]

My thought on the twin plug was that it runs cooler . I also thought that a Centrifugal compressor would have some of the same lag issues of a turbo. It would definitely be easier and cheaper to engineer...

[clutch-monkey]

got told a centrifugal charger, when sized correctly, basically matches your N/A power curve.. there's just.. more of it.. would be kinder on the gearbox for sure?
have seen some cars with big ones fitted, and yep, all top end power.

[Mick_D]

My experience with v8 motors is that roots type blowers spread the boost more evenly over the power curve than centrifugal blowers do.

[jsveb]

Far from an expert, but I would go for a centrifugal style as well. If not for performance characteristics, then for pwr delivery. I think the 2.7 engine and 915 would prefer cent. Tq delivery over roots or twinscrew.

Search for DPHans to see what turbo pwr he gets out of a 2.7

[Rodsrsr]

clutch-monkey you are absolutely correct. Just made the 3.2 feel like a 3.8. As far as lag goes there is none because its still a normal compression 3.2. Lag is almost a non issue nowadays anyway. When people mention lag they are probably thinking about the early 930's with ridiculously low compression. (which is what caused the lag)