This guy seriously can't see the difference between Brett's observations and his own insults. Is that a common trait of a Sociopath?...that's not an insult, just and observation.

You guys dish out your own plenty too. It wasn't an insult. Just go back and read what was posted when the last boom happened. Frankly I'd have felt the same way. My technical opinion was to try and help him avoid it again, but let's all just jump in and stir it up way bigger than it has to be and try to blame someone else rather than let him and I work it out on our own. Or is that your own insult; he can't handle it on his own?

Was there ever any discussion around this anywhere? What happened with the other two engines? detonation?

Probably rebuild integrity issues, but they also could have been damaged to the brink of failure prior and just finally let go under those circumstances..

How about we let the "tussle" go gents?

Build integrity... nope.. More like a desire to push boundaries. And continuous mods.

I'll let Brett answer though.

Enjoy gentlemen, play nice.

Travis

I was mostly referring to the two engines 9k mentioned. Obviously Brett's trying new things, and blowing stuff up is all part of that.

Anyway ................ I got the dual exhaust modified and have tested it . Really happy with the sound now . The pulsing you hear in that video on the previous page has gone . Power wise ,from VD it looks like a small gain ... not sure if it's enough to make another trip to the dyno worthwhile however.

so what did you modify?

I split the flow from the wastegate pipe so that some of it diverted back into the main pipe .
In hindsight ,I really needed a bigger pipe for the WG . Or just going to a 31/2" exhaust would have worked better too .

So after everything I've done to try and get more power from this engine I now believe that adding the bridgeport is the thing that has set me back the most. I thought maybe the exhaust was an issue but the gains i see from resolving that aren't significant . I just can't seem to get the car back to what it was before the bridgeport. Both in spoolup and peak power.

I believe 450whp peak (400 reliable) and fully spooled by 3000-3500 can be achieved with the setup I currently have . Unfortunately , that will require another engine build and while this current engine still goes strong that is unlikely in the near future.

Sorry to hear it, Brett. You're one of the most dedicated renesis guys out there, I'm sure you'll get it sorted.

Do you think that the Bridgeport increased the area too much, slowing down your exhaust gases?

Cheers Chris.
There are a couple of things that are working against us in a Renesis bridgeport . One is the in chamber pressures at high rpm/high power which I believe are a higher than on a PP engine . The second is that there just isn't enough overlap to make it work . There is time for the exhaust gases to pulse into the intake but not enough time/port opening to send that contaminated pulse back into the chamber with interest . The net result is you get more EGR instead of less .

A larger turbine would definitely help , but not enough to actually make the BP beneficial . IMO

Now that I've gone as far as i want to go with this build I think it's time for a bit of a summary on what worked/didn't work .

Siamese wastegate/twin scroll turbo :
From data i have it is obvious to me that I haven't unlocked any extra power up top by doing this . Then again I don't believe I've lost any either . The power the engine makes is as good if not better than anything I can compare it with . Low to mid range power being better than any other Renesis that has a similar top end , and also better than most with less top end potential as well.
Improvements in spoolup when paired with engine port timing mods are definitely there and are significant . I believe there are even further big improvements to be had here with the right engine modifications.
Improvements in boost control were an added benefit .
Overall , based on the improvement to spoolup alone I would say this modification is a success .

Bridgeport :
As mentioned above , this modification was very disappointing . I believe I lost somewhere around 20whp across the entire rev range by doing this . A slight reduction in spoolup/response being an added downside.
One surprising side effect that has been beneficial is fuel economy . I get really good fuel economy with a 30% ethanol blend . Mileage being as good if not better than any stock NA Renesis on 100% petrol.

Turbo :
I have tried a few different combinations of turbine housing and compressor wheel in the GT3582r base turbo .
In the final analysis I saw only minor improvements going from the stock GT 35r wheel to a billet GTX3576r wheel .
I found the larger 1.01 AR twinscroll turbine housing to be superior to the 0.83 in all respects .
The slightly better spoolup of the 0.83 did not translate to more power at the wheels in lower rpm ranges as you might expect.
For a low mount turbo the GT3582r AR1.01 with a To4B compressor housing was a good choice for the 350-400whp level . Fitting a better turbo (eg BW EFR ) down low would require a lot of firewall modification .
One day we'll see some great results from a top mounted EFR that will better what this setup is doing ........ not holding my breath on that one though.

E30 :
Running this compromise blend was a biggie and I would recommend it for anyone running similar boost in a Renesis . I think it's been a great compromise between fuel consumption , fuel system requirements and octane for a street driven Renesis running over 14psi boost.

Two stage exhaust system :
After my latest modification to this I would have to say that I would definitely do it differently if I was starting over . The simplest and cheapest thing I could have done would have been to just go straight to a 31/2" exhaust ...perhaps split into 2x 3" mufflers at the rear .
That said , the setup does produce a unique sound for a Renesis that I really like . It is no longer obnoxiously loud nor is there any drone at highway cruise . Not worth the expense though , I have to say .

Key finding from this project :

Pushing this engine to the limit has been a frustrating exercise and it has been through bitter experience that I've learned this one piece of information that I would like to share .

When dynoing a Renesis engine at elevated airflow (over 420g/s approx.) the exhaust ports start to become overwhelmed and chamber pressures spike within the engine. This set of circumstances is unique to the Renesis and is the main reason why getting big whp numbers has proved so difficult . This probably isn't news to most of us but how to best deal with this such that you don't blow your engine might be .

I've found that I can run much higher power on the street than when on a dyno . The reason being that on the dyno the ramp rate is set to match a 1:1 gearbox ratio (5th gear) so the amount of time the engine spends at elevated flow is much greater as compared to the street where 3rd gear (100mph) is normally as high as you would go . It's this extra time at high internal back pressure/elevated exhaust temp and high rpm that does the damage and can cause a catastrophic failure .

The solution is actually quite simple . When dynoing at high flow/boost ............... have the dyno operator abort the run as soon as peak horsepower has been obtained . Don't go past that rpm .

Then as an added safety measure set your rpm cut to just after that peak rpm for the street .

FWIW .... I've set my peak rpm at high boost to 7600 at which point I've programmed the Wastegate to open . Actual rev limiter is set to 8300.

I know we have our differences wrt certain technical concepts and details, but your shared efforts, expense, and results are extremely commendable and a huge benefit to the Renesis engine community. :beerchug:

So for a low mount the GT3582r is the way to go? How much of the gains would you attribute to the twin scroll manifold?

Have to admit that my initial thought when reading this was ... "who are you and what have you done with Teams' body ? "

Yes we do disagree on a lot of stuff but that is not necessarily a bad thing as the resulting discussion/argument often leads to some clarity of thought for me . Thank-you for that and for the above comment.

The main thing about the GT3582r that makes it a good choice for a low mount is the physical size . It was the only decent turbo with suitable flow I could find, that is available in a T3 twinscroll ,with the option to fit a small compressor housing.

I am guessing it is between 500-1000rpm spoolup improvement from the twinscroll . Bear in mind that without engine porting mods a twin scroll is ......... useless.

Thanks for making such an effort to share your experiance, its been a great read.

So a 3076 in the same size housing wont support 350whp?

It took a mad scientist to make an engine with three exhaust ports work on a twinscroll manifold!

well you might get to that whp but it would be on a knife edge. 300-320 would be more realistic reliably.

haha , more of a masochist

WOW, what a read and a huge pile of information to absorb. Your persistence in this project is incredible and many of your ideas were very forward thinking even if they didn't always work out.


:score:


Additionally thank you very much for sharing all of you trials and tribulations it will benefit anyone who reads this thread.


I gleaned back in the last intake mods the engine mount and intake to the turbo had been redesigned. Did it end up a straight round tube or was it oval shaped somewhere so it would fit? (you probably mentioned this but I missed it)


North

Thanks . There is quite a bit I haven't even talked about in here btw.

The intake tube ended up pretty much round after a few changes here and there. It seems to be lasting ok so far but is probably a weakness in the setup i'll need to address at some point.

Agreed, well said!

I like this new kinder, gentler TeamRX8. :)

Brett: awesome job as always buddy and thank you for always taking the time to share your experiences / findings and never being afraid to challenge this engine