Ok, as i said just before i have a brand new CV in stock (for my other 951 normally but that will be perfect to test). I may replace it this saturday, i'll keep you informed.

Thanks for the replies

 

Nonono, I meant the CV (or actually the program on chips that control the CV) is designed to give proper boost with the original wastegate, which has a weak spring and requires less pressure to open than the updated guru wastegate.

The vacuum/pressure hose off the intercooler pipe goes to the wastegate, through the cycling valve. The chip's program opens and closes the cycling valve, thus limiting the amount of pressure that reaches the wastegate. It does not know anything about the actual boost, it just runs the pre-defined pattern - so now that you have a stiffer wastegate, the control pressure that kept 17psi of boost with the stock wg ends up giving a lot more boost.

I hope that makes any sense, english is not my native language and automotive jargon even less so (je ne parle pas francais either, tried learning in grade school but you guys speak too weird )

 

To : macnewma


The AccuBoost is the new boost controller we have just released. It has not yet been posted on the website, but will be by the end of this month. Certain distributors are selling this product, such as speed-6.com. This controller supercedes the ReliaBoost II by leaps and bounds.

If you have any further questions regarding the AcuuBoost or any of our products, please feel free to email us or post technical questions on Rennlist.

Regards

 

Hi Sami,

It makes sense, no pb, i understand what you mean now
So my only way to solve the pb is definitely to bypass the CV is that works like this. Or to get chips (i have the guru chips but not mounted in the car currently) able to manage that

 

Great, i have a question for you BoostSciences

I also have a Reliaboost II and we tested it, at the maximum rate (harder) it opens at 0.7 bar approximatively. Impossible to make it open later. Is it normal ?
BTW, we didn't test the Accuboost yet to see the difference..

 

What modifications were made by the factory to upgrade the cup cars to 305hbp?

Just the chips and 3.0 bar FPR?

I thought I read somewhere that there were also modifications to the waste gate, or an upgraded unit that the factory used to hop up the power.

 

Main mods were KLR/DME, spark plugs, fpr, wastegate, exhaust, intake manifold...

 

On my LBE Boost Enhancer you are meant to REMOVE the banjo bolt.

 

Asarus

We had the exact same problem: shimmed WG, Reliaboost, Guru chips, and 3 bar FPR, and the thing ended up running 1.5 bar (22 PSI), even after we backed off the Reliaboost. I was stupid, so I continued running and racing this, saying to myself that I could back off the boost - so blew the 12 year old headgasket (nice lot of smoke, that).

New HG, bypassed the CV, got rid of the shims (not necessary, I think), and put in a manual boost controller. That did the trick, it now runs at 1.15 bar, which I suppose is ok.

Do yourself a favour: reduce this boost level, it is really too high. We were running 55# injectors as well. Ultimately it was the heat that did it, I think: on the aftermarket oil temp, we were registering 115 degrees centigrade - reason that the car now has two mocal oil coolers with ducting (left and right).

Hope this helps

 

To : Asarus

Yes, you can make the ReliaBoost open later by upgrading the spring. Guru Racing provides the upgraded spring and so do we. Not all users need it. Usually the people with better wastegates need it and benefit by it. PM me if you need it.

Regards

 

Thanks

I will try if the Accuboost do the trick (i guess so), if not i will PM you

 

Thanks DrRon

Don't worry, i have absolutely NO INTENTION to run with this boost level. My Cup car is in mint condition and i don't want to take any risk with it (even the smallest risk). That's why i don't use the car currently. I just did 4 tests with the accuboost set up at different boost levels. And i didn't even accelerate more than 2 or 3 seconds each time. A friend of mine was passager and monitored the boost level and AF ratio. Once we saw the boost wasn't correct (as i said, 2 or 3 seconds max), we immediatly stopped, and tried a different setting.

I won't use the car until i got my NORMAL boost level for this car meaning 1.1 to 1.2 bar (16/17 psi). If i have not the solution before my track event, i won't go to this event !

So the next step is to bypass the CV, set up the accuboost to minimum and test. If that's ok, i will adjust the accuboost. If that's not as expected, i will put back my old wastegate and stop.

 

>"Main mods were KLR/DME, spark plugs, fpr, wastegate, exhaust, intake manifold..."

My understanding is that the 305 bhp cars were upgraded from the previous 250 bhp Cup cars, correct? Not new cars. Out of curiosity, what was changed on the intake manifold and exhaust between the two versions?

Im guessing the factory upgrade was a stiffer spring in the waste gate, or was it more substantial than that? This unit was still leaking boost at higher rpms? What did Guru change on this unit, or did he just rebuild a stock/standard model waste gate for you?

Sorry, this is slightly off the topic, but Im just trying to understand what the factory changed/upgraded in order to run higher boost to generate the 305bhp using the Cycling Valve setup.

 

You're right... the 305 bhp Cup is the ultimate evolution of the Cup cars. All the 305 bhp cup cars were 250 bhp Cup cars when leaving the factory...
The kit was then installed by the french company (Snobeck) in charge of the Turbo Cup trophy for the last year (1990).

The intake manifold is a magnesium part but the same than 250 bhp cup cars
The wastegate was modified but i can't figure out how ... the most credible is a wastegate with stiffer spring.

My car has the stock shimmed wastegate. Probably a 250 bhp model, because the cars had to be in 250 bhp config to be street legal. Mine was re-setup in 305 bhp just after the homologation

With this stock shimmed wastegate, i got 304.6 bhp on the dyno in september.

If i change the wastegate for the danno one, that for several reasons :
* replace the shimmed wastegate by a wg with stiffer spring and no shim
* replace the used wastegate by a new one (the one with stiffer spring) as a preventive maintenance
* keep the boost at a correct level. Currently i've seen my boost level drops to 0.7 or 0.8 bar to redline. Probably because my current wastegate is a bit old now. I should get 1.1/1.2 bar to 6000 rpm and then 1.0 to 1.1 to redline to be ok.

 

I'm new... but I *thought* I read that once you exceed a certain boost pressure you also need to upgrade the fuel injectors??

I *thought* that increasing the boost forced more fuel and air into the engine. I also *thought* the default injectors maxed out close to 17psi for the amount of fuel they can provide.

Is it possible that the high boost that you are running is calling for more fuel than the stock injectors can supply?