Hey Guys,

Quick question for you all. I recently got dynoflashed by Al, and couldn't be happier with the car. It accellerates like nuts, and I'm redlining before I know it.

My question is in regards to boost taper. One of the advertised features of the dynoflash was that it held boost at peak until redline, or at least the best that the turbo could manage. However, my boost still seems to be tapering off to about 16psi. I also have a MBC, so this should prevent this from happening. Al said that even the best turbos taper naturally, but I hadn't heard that in any of the posts I've read through. Most people here say their boost holds steady at 19.5psi.

Is something wrong? Do I have a boost leak or something? Any help would be appreciated.

Thanks,
James

 

I got the flash too - rocks. I don't have a boost gauge yet, but it definitely pulls hard to redline. It does, however, feel like it tapers above 5k.

 

I called Al about this when I had a Dynoflash and he told me my MBC was faulty. So I kept my MBC and switched my flash and now it holds perfectly. PM me if you want to know what flash I got instead and how said company will help you out.

 

I'm guessing "said" company is Turbo Trix?

I'm down to hear if they can fix this.

One more question, since I'm here. I also noticed that my boost guage sits in the vacume unless I am accellerating hard. Is this normal? I was under the impression that at normal speed (steady of like 3K rpms) that the gauge would read at least 0 boost, if not something like 3-5psi. What's up with this? The gauge seems accurate at WOT, with it peaking at 19.5psi (and then tappering off.)

 

Can you tell me what are the exact mods on your car ? Lets see if we can get to the bottom of this - thanks

 

You have an MBC and it doesn't hold boost, but yet you're suspecting the flash?? Are you serious?

There are plenty of people in this forum who are running their Evo's with no flash or engine/fuel management using a MBC. Many get steady boost, most only a 1-2 psi taper. Your taper is too much. Look into the MBC as the culprit, or you have a boost leak.

As for your gauge, yes it does read in vacuum unless you get into the throttle aggressively.

 

I am confused as to IF he "has a MBC" or has a MBC INSTALLED IN the car as in his signature it lists a HKS EVC

In any event - in 99.99% of cases with our flash if you ADD a external boost control unit - if there is any tapering evident it is related to your boost control or the install

of course there are exceptions

Cars are complicated machines and there are many possible sources of these kind of conditions

This is why i'd like to start off with a list of mods for this customer

BTW - generally our base flash, which is using a FACTORY OEM boost solinoid can only delay and slow down the factory boost tapering. What this means is that we enter a setting that slows down the factory electric taper on the solinoid which is normally programed to lower the boost during your pull through duty cycle. Even after you take out the electric taper - due to the design of the stock hoses and restrictor pill there is still some tapering going on.

This is why some vendors use so called "pills" to modify boost which I do not like as I have seen high booost spikes in some cases with that method,

With my flash alone I can not adjust the boost or stop the tapering 100% - we only slow it down by stopping the factory electric boost tapering.

Thats we we recomend the Hallman MBC - you have very good boost control with that unit and miminal taper. With the CORRECT Hallman unit - and a correct install (very important) your booost would not taper beyond a nominal level (unless you were having detonation issues and having timing pulled).

 

Thanks for the response Al. Despite what it says in my signature, I actually have a Hallman MBC (I just wrote that in my sig to be clever...or not) The MBC was installed by Pruven, along with the boost gauge. That's why I was wondering about the taper. I also have a custom dynoflash. (Mods are turboback exhaust and AEM intake.)

You mentioned during the flash that my fuel pump was starting to tap out, which is why we couldn't make more than 290whp safely. As mentioned before, the car pulls hard, and I am very pleased with the dynoflash, but the taper is still very evident, which is why I am confused. Not sure what I should do. I haven't touched the MBC since it was installed. Any help would be appreciated. Thanks.

 

In your case - something must be happening on the street, your bov must be leaking or you may have developed a boost leak. Also - your stock fuel pump may have further deteriorated and you may now be running lean on top and the ecu pulling timing. That would also be a dangerous condition so I want to get to the bottom of it quickly. We really like to see all the evos with the upgraded fuel pump that we tune on the dyno. Its regretable that we had no stock when you came by for your tune. In cases where the stock pump is alreay starting to fail - often we see them start to go worse and it throws off the tune.

I will be at Pruven most of Monday and Tuesday this week

Give me a call - and we can arrange a meeting to look over your car. It will only take me a few minutes to find the problem

With that Hallman and a install by Pruven the boost should be almost rock steady till just about 7,000 rpms then it should gradualy taper down one psi to the red line

 

Thanks Al, I'll be giving you a call.