user1029

BGB Motorsports

On today's episode of How Did They Do That, we dyno compare the first 4.0L X51 we did vs a Cayman GT4 Clubsport MR. The Spyder came back from California for some additional tuning, intake work and cylinder head porting and we did a dyno test before shipping it home; it's still however running 91 octane and has a CEL ONLY for the catless race header setup! The Clubsport to which it's being compared is running 98 octane VP race fuel but is about as close to a stock GT4 as you can get other than running 100 cel cats vs. 200 cel and running the race gas.

switchface

John - if someone in California is interested in one of your Stages, do you have local SoCal shops you would suggest for the installation/tuning to avoid having to ship the car cross-country?

James88

wow !! 428 at the wheels, that would be close to 500 at the fly wheel.

G-forceGT4

Holy crap! Look out GT3's, we're coming for you : )

James88

I just recalculated that. Correct me if I'm wrong, you loose between 15% to 20% HP from engine to wheels, yes?
This makes the engine power between 504hp and 535hp !!!!!

ajw45

The 4l x51 is awesome, I love mine, but it is not 535 hp engine. All dynos read differently, people should ignore the absolute numbers and look at the hp and torque differences between the clubsport and the 4l x51 car as an indicator of the gains. Thats why its great that bgb was able to provide a dyno of both cars run on the same dyno.

James88

Good to hear you're enjoying it.
There's still quite an improvement when you compare it to the Clubsport. There's a difference of 76 HP to the wheels.
The 4L x51 was tested on 91 octane and the CS on 98, that's quite impressive.

ShinAsurada

so there is additional porting done to the x51 cylinder heads and others to achieve this? I thought it was just an X51 installation.

BGB Motorsports

To date we have not done any remote work; i have a gentleman's agreement with the other shop in the country that does this conversion in the northeast to not sell the 4.0L bits and i am holding true to it. My X51 file alone has probably 100 hours in it making the car look and drive like stock as if it were born that way. Some of my greatest IP is in AJW45's X51 4.0L file and to this day DeMan and i still share informaiton. To be honest, one of the biggest reasons we are still around is because people send their cars to us from all over to have this done. If i partner up with a shop, my fear is that it will cannibalize our own business potential. It still happens...customers will call and take my quote with the parts list and take it to their local shop to have other work done and they try and pay me a consulting fee but i end up spending more time on the phone helping them and the customer always circles back and says "you would have charged me less to do the job better and i should have just come to you!" It's easy to tell when someone does this and tries to retrofit the X51 themselves because i get a call asking why their car doesn't run smoothly and then i say "sorry about your luck."

I use a very simple 12.5% drivetrain loss number to come up with 489 crank horsepower and 361 lb/ft. What's crazy is that my Dynojet runs always always always read lower than everyone else's because i'm in the hot Florida sun outside where it's humid and Dynojets are heart breakers that don't pump out ambiguously large numbers. The intake air temps on this run were 99F. This car on an indoor dyno in the northeast sucking 70F air running better gas would be another 15rwhp - 20rwhp stronger than this. The fact that it's running 91 octane and still made this number astonished me. I was expecting 420 and would have been happy with that but to get closer to 430 made my day!

That's the entire idea behind this conversion. Trying to put a 991 GT3 motor in this car would cost over $100K in electronics, engine work, bodywork, etc. Moving sump tanks and making things fit would be a nightmare.

I use a number of about 12.5%. So I think we are at 490/360 crank. I've used this same number since 2004 - i always dyno in 5th because it's as close to 1:1 as we can get with this transmission.

Agreed! I wanted to put the Clubsport up there to give it some perspective because it's a known entity. The Clubsport makes MAYBE 5rwhp more than a stock GT4 because at the end of the day, that's what it is. It's running stock filters, stock intake, stock exhaust (except for the slightly better flowing cats); the only difference is the race gas. It's awesome when you chime in because you always support this product because you have one and you love it. I can market all day long but there's nothing better than customer testimonial. Rick and I share so much information - you're driving the same thing we are dynoing. I'm glad you're loving it.

I think that's the thing that really impressed me. We could make a lot more power if we weren't running 91 octane but it does me no good to tune this car even on 93 and send it back to LA like that. This car was always about 5 - 7 rwhp less than the others because i had to literally go to the pump and put 91 in it which i never ever do. This car on 98 octane would be insane, especially without the humidity. No wonder the owner loves it; i was hesitant that he would be imrpessed because he also owns a turbo McLaren but he loves the high revving NA motor. The data though is just as you said...peak vs. peak is substantial but because of how much power the stock GT4 intake bits lose at 7K RPM, over 7K there's a massive difference. 62lb/ft of torque at 7300 RPM is ridiculous in my opinion. These motors are easy to make power with but getting torque from them has been like getting blood from a stone; X51 + 4.0L is awesome at achieving this!

Yes. The car came back for some intake work to try and achieve some power gains and I made the decision to send the X51 heads out to my engine builder to have them opened up just like we did on our 2013 race motors. While the X51 heads are advertised as already being CNC ported, we did more intake porting and substantial exhaust porting to match everything up. I think that the porting was worth about 15rwhp. The car was originally a Boxster Spyder that showed up here to have the X51 kit installed (intake manifold, cams and heads) and the 4.0L bits (crank, rods and pistons). It went to California for 2 years and then came back for the porting and to have some ECU work done. I wanted to look at the engine and i wanted to dyno it to make sure it was a strong as it was the day it left and it was but now it's even stronger.

user1029

NelsonF

So tempted for my 981 Spyder. Probably good that you aren't in Cali. Any service could get pricy.

sdillon

^ This. BGB, you will be getting my car and a check some day for the 4L X51. We'll play with the stage 1 bits for a season, but after that...

switchface

Makes sense, got to protect that IP for sure. I'm guessing its ~$1k per direction to ship a car cross-country, so its looking around $50k + tax to have the full monty shipped from left coast to east back and forth?

RichFL

As a customer of BGB I highly recommend shipping your car to them and let them do the work. You won't regret it.