Boost Controller Gives Me A Surge

[gargantua]

Hi guys

I installed a boost controller about a month or so ago, Its one of the new Blitz SBC ID ones. After doing that the car missfires at around 4000 RPM sounds like its farting, but thats not a problem because I am going to buy some Splitfire packs that I think it will get rid of that problem. What I am concerned about is that car surges more that it missfires its like a loss of power for a second and the car jerks (very embarrasing), is this a fuel cut thats happening?

If so what can I do to fix this problem. I do not want to buy an aftermarket ECU.

[(B1) MR_fanny]

what boost are you running? turn it down? sounds like boost cut

[J_Red33]

I'm having the same issue with my blitz SBC but it's nothing new to me as I had the same problem before. You've probably got a tune on your SBC that's too aggressive. Have you checked your boost graphs at all? I get the dreaded rich & retard (not boost cut, that's a full momentary shutdown) at about 4800rpm due to there being a boost spike to do witht the cam kicking over.

I've wound back the gain & it has suppressed the spike, but it is boosting slightly too high still at that point. A bit more fine tuning & it should be soughted.

[(B1) MR_fanny]

interested in your setting j-red. ive got a blitz dual sbc and im getting reliable boost with a 45/12 ratio. any higher on the gain and i feel like i loose performance. strange cause the turbo spools faster but doesnt feel as solid.

[J_Red33]

I'm running the SBC i-Color myself. I'm running it in auto mode at the moment & just setting the target boost level & gain. There is a lot of settings on the thing so I've still got a bit of playing around to do.

I'm surprised yours feels flat when you turn the gain up. Mine gave a solid kick in the ass when I had it up at 20 (probably a bit high for a stock turbo but didn't spike) but the boost level was starting to run away when you hit 4000rpm & peaks at roughly 4800 (the graphing function on this thing is gold). I'm running a target boost of about 10psi & I've turned the gain down to 12 but it's still not quite right yet. Raises boost by about half a psi in the same rev range still, which is just enough for the R&R to kick in.

I'll also add I'm still running the side mount intercooler, which seems to be affecting my boost levels depending on the ambient temp quite a bit.

May take me a little while to sought out 100% yet, but I'll post up what I find is reliable as a basic setup.

Edited March 29, 2008 by J_Red33

[gargantua]

Im running 12psi most of the time. But it even does it on 10psi and even when I turn the controller off. The funny thing is after I have been driving for a while it wont do it anymore. The tuner who installed the controller said on all skylines when you increase the boost it runs Rich & Retarted.

[J_Red33]

Well I've got my tune pretty close to nailed now. Only running a target boost of 10 PSI at the moment, but I found that if I wound the gain down to 9 with the target set at 10PSI, I get very minimal variation in boost & there is absolutely no issues with Rich & Retard.

Having the SBC I-Color I can do RPM based boost mapping so I'm now running a dual map with Gain set to 20 up until about 3750RPM & then down to 9 above that. This set up gives me both a snappy bottom end (full boost as low as 2100rpm!) while maintaining acceleration throughout the rev range. Boost graph is almost dead flat apart from a couple small dips of less than 1psi.

I think it could be even better yet & I may go as far as making 3 or 4 settings for different parts of the rev range. However before I do this I am going to try a similar set up with Manual mode.

Edited April 4, 2008 by J_Red33