550 Dyno update

Just a quick update while I wait for she who must be obeyed to make her self beautiful before we go out this morning.
The 550 has Tubi rear mufflers, custom crossover pipe and BMC filters only.
My base run last year showed an estimated 486 crank hp (290kw measured at the wheels). The latest run this morning after adding the crossover pipe is now 542 estimated crank hp(322kw measured at the wheels).
All runs have been on the same dyno, calibrated the same etc etc. Coincidentally atmospheric conditions are almost identical.
I only realised afterwards that I had left the airconditioning on, so will do another run next week, with aircon off and with a different crossover pipe design.
I'll scan the comparative dyno graphs and data plots later this evening. Got to go and enjoy my Saturday with the family now.

 

PS, tubi rear boxes only fitted. Stock cats, headers and link pipes still used.

Base run was with stock everything right?, or did base run include BMC air filters and tubi rear boxes??

pps, its she who must be seen to be being obeyed.....!

 

Base run stock car, no Tubi, BMC etc, that's why it's called the base run.
Sorry edited Tubi exhaust in first post to rear muffler only, forgot Tubi makes full systems.

 

Dyno graphs
1. Base run, standard car.
2. Tubi's and BMC filters.
3. Tubi's BMC filters and crossover pipe version 1
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"she who must be obeyed" - you a Rumpole fan?

That's a big power increase - looking good.

 

Bloody hell!

 

I'm amazed too. My @ss dyno is not too far off then!!

Not sure what the A/C is worth, less then 10 though, surely?

Mk2 siamese pipe won't give any more power I don't think, but I think it will clean up the noise, as it's a little "Lambo" at the moment. (Rough!)

 

What is causing that dip/spike in the upper RPMs?

 

Cutover on dual length intakes. Ecu triggers a vac operated pushrod that lengthens intake stacks in plenum. I'm going to have to get someone to make a an adjutable controller so it will cutover about 500-1000rpm sooner

 

Very cool, that's a huge rush of power for being so high up in the revs. I bet it makes it tough to avoid the rev limiter!

 

My father was a pommie through and through. Grew up watching Rompole, Dave Allen, Benny Hill etc.

 

Look forward to following you coming off turn 12 at the Island next month!

 

Stephens - that's pretty cool.
I wonder if the first 30bph is due to the air filters or the tubis. If it's main the air filters it sounds like filters and x-pipe would be the best bang for the buck!

What's next? You could get up to 580-600bph without much more work

 

Syd the Tubi's aren't worth any power, it's the BMC's and the centre pipe section. I've previously posted a pic of the pipe in front of the mid muffer from my other 550 cut through to show a huge restriction where Ferrari have crimped the pipe.
I'm going to play with the ECU next weekend, contrary to what I initially believed, the ECU is adaptive as the car was running much richer this time. There's at least 10-15hp left from leaning out the AFR from 5K up.
I've also got to work out a deal with Phil on his spare 550 intake. I have a friend just outside of Geelong who is a genius on the flow bench.
My current thinking is ECU tuning 10-15hp, race cats 10-15hp, reworked intake, larger (bored out?)throttle bodies 20-30hp. So yeah, I'm quietly confident of a 575-600hp result, without opening the motor. Who'd of thought??

 

Obvious question: does the 550 feel any different acceleration wise?

The 612 and 575 HGTC boasts more power from basically the same engine. And Phil reckons they're bullet proof, and if the 355 Turbo experience is anything to go by the V12s should also be bullet proof.

The 550 is a bloody underrated car. You'll have a ball at PI next month - pity I'll be overseas. Here's a pic of the island almost 3 yrs ago when there were 4 550s down there (3 in photo)! Sadly a sight we'll probably never see again.
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Do you think the rest of the car will cope well with a 100hp increase (handling, breakes) ?

 

It's really noticeable that it doesn't feel like a slug, particularly through the mid range, compared to the Merc anymore.

 

Suspension already upgraded. Braided lines and Pagid pads on the brakes. I'm trying to avoid a full upgrade, but I think this would become the next step. i also want to find out if the larger brake booster/MC from the 575 is a bolt in fit.

 

Having got under the skin of a 575 this week, I think the single biggest improvement that's worth working on with a 550 is larger throttles and air intake, (after the air filters and exhaust centre of course).

The 550 has 72mm x 2 while the 575 has 84mm x 2. That's a HUGE increase in available flow, and also indicative of why the 550 responds so well to better filters. It's strangled. (Shares the same filters as a 355).

My spare 550 intake is begging to be bastardised............!!

I also took over 3kg off the flywheel of the rebuild job I did, and that car was a little more lively too.

 

Geezus christ Stephen - how on earth are you deriving so much power? I'm going to have to try BMCs in addition to my x-pipe / CG...

--Dan

 

So a pair of these dudes for 30hp ?
Comparison of the #1 and #2 curves shows no loss low down and a meatier curve from 100kph which is really low down if the run was done in 6th.
Looks like that would be 220 well spent US$ ...
What's the downside ?
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Phil:
You mean throttle bodies? or MAF sensors? I'm just a hack, not a tech, so correct me here. 612/SA get even more, similar intake runners. Are the 84mm TB's easy to swap? If so, what a boost! 25% greater intake area. Man, that would be cheap bhp. Hmmmmm.

 

Where can I get BMC filters in LA? I have been waiting over a month so far and I am being told that they are back ordered. Is there a website, etc? Thx

 

Phil is talking about the throttle bodies themselves, however this does incorporate the MAF sensors. The best we can achieve on the 550 is by machining. I wouldn't like to imagine the cost of a complete 575/612 intake assembly retrofit to a 550. I would hesitate to suggest the motor needs an increase in throttle body size to 84mm as this equates to an increase in flow of approx 45%. An increase in size to 75mm, which would require the removal of 1.5mm of metal only, would increase flow rates by 10%
The only way to know what is going on is the put the whole assembly on a flow bench to work out what specifically the intakes do flow. Calculating flow requirement for the motor is a simple process.

 

Agreed retrofit is not feasible for 575/612 TB's on 550---Later cars have electronic TB, so not compatible. I took my car to dealer to look
However, opening up TB is fairly simple, as long as you have someone who knows what they're doing, and you resist going too large, as you get weird idle problems from eddy currents around throttle plate. Did it on my Works S Coop, and it works a treat. Probably could go 78mm? How big/compatible are 355 Challenge TB's?? hmmmmmm.