gmsracing

I've done a bit of searching, but I'd like to ask a few questions:

As received from a previous owner, my car has an Authority MAF, chips, k26#8, 55 lb injectors, 3 bar fuel regulator, a 2.5" exhaust, and a Lindsey single port wastegate. I'm running a nominal 1 bar (15psi) that bleeds off at higher rpm.

If I get a dual port waste gate and a boost controller, will it allow me to hold boost to redline? If so, are different chips needed to support that?

I think I know the answer, but I just wanted to double check what the latest thinking is. I don't have a 3" exhaust now, but I'd like to get one soon.

joker2cv

You can hold pressure at redline with a single port WG just using a manual boost controller, but you have to pay attention at AFR...

ChrisJ951

Get an air/fuel kit like a zeitronix. You don't want to run the motor lean.

gmsracing

Thanks for the inputs. I have a older (forget the model) air fuel meter that is installed on the car. I'd have to check it out tonight to see which one it is. Regardless, if one would either run a dual port or plumb up a single port with a manual boost controller and run higher boost in the higher rpms, I would think you would need to retune/remap things at that point? True? The authority MAF has a **** that can adjust things but I don't have much info on that yet. Or, does a new chipset cover things?

bebbetufs

From what I remember the K26#8 in standard form is not able to hold boost to redline. It is not efficient enough. You will need to get a modded turbocharger to be able to do that regardless of your other mods. With a dual port WG the car will pull harder because it will build boost more quickly since it is not bleeding off pressure before you want it to, which should be just before the max boost you are aiming for. And because you can increase maximum boost not allowing the WG to open before a higher pressure than stock has been reached. However, the WG cannot improve the efficiency of the turbo itself, only help it reach it quicker, so it will begin to taper off before redline is reached. Basically the engine is ingesting air faster than the turbo can compress it.

gmsracing

Well that sucks for me that the k26#8 won't hold boost until redline!

Dougs951S

This is not true, the k26/8 is completely capable of holding a reasonable max boost level to redline. Your waste gate is not holding if you are having an issue. Also do get a proper boost controller and ditch the cv and klr controlled boost control.

by the way, are you still running the factory cat in that stock exhaust? If so ditch it and watch both your spoolup and boost holding improve from the reduced backpressure.

bebbetufs

I'm sorry. I did not take the boost level into account in the above. How close to redline the #8 will be able to hold boost will of course depend on the PSI level you're aiming for. I assumed you wanted to increase boost as well as making the boost hit harder. If you are sticking to stock boost you should be more than fine.

Some info:
https://rennlist.com/forums/8992430-post51.html
https://rennlist.com/forums/8990798-post49.html