Advice / Input

[Chev R]

Advice / Input

Hey Guys i'm new to the forum and need some help if you don't mind. I live in South Africa

I currently have an Rb 25 Det lemme give quick run down on spec's.

Sub Assembly skimmed 1 mm Rb 26 pistons 86 mm COMETIC Head Gasket

Head done ported and gas flowed cams cut 270. Done by Steve Clark No Sweat Racing

Head currently has all Rb 26 parts , Valves , Quarters , Retainers , Valve Springs , Lifters etc. So Head is Solid Cams and Lifters. Head can probably rev about 8500rpm+ but oil pump is stock.

Branch build by Marius from Full Boost 3 into 2 into 1.

Turbo Garret 60-1 T4

Bosch 750 cc Injectors

Bosch 044 external and Facet in tank pump

Rb 30 Clutch and Pressure Plate

40 mm Wastegate

Custom Intake Manifold

Intercooler

Spitronics Engine Management 60-2

70 mm Exhaust

Currently has 1 Bar map on 95 ctane pump fuel. Took the car for Dyno but was spark breaking on the Dyno will replace this weekend.

Not sure if any of you have similar set ups. So this is where I need some info please car will be going back to Dyno soon

I will be Changing Fuel to 50/50 95/Ethanol

What do you guys thinjk Rb 26 pistons can take max boost?

I'm looking to try and push for 1.2-1.5 bar boost is this ok?

What Hp should I aim for safely?

If you guys can assist with any input will be highly appreciated. Sorry about the book tried to give as much info as I can

Thanks

Brian

[Steve85]

Hello. I'm not much help to you but what kind of car do you have? It looks cool!!!

[Chev R]

Hi thanks man. It is a 1972 Chevrolet 4.1 Limited manufactured in SA and Australia also had them.

[Steve85]

Hi thanks man. It is a 1972 Chevrolet 4.1 Limited manufactured in SA and Australia also had them.

Awesome, I'm not a huge muscle car guy so would never have managed to guess. I hope someone here can give you some guidance.

[Chev R]

Thanks and I hope they will assist me. Unfortunately had to do mod in there because they never brought R32,33,34 to SA. We can only buy the engine's here or import the car which is very expensive. I would like to own a R34 Gtr Vspec though

[KiwiRS4T]

1.5 bar is nothing - do not go by numbers - your tuner should keep increasing boost until it becomes counter productive and similarly tune to max with regard to exhaust temps knock control etc. You will get what you get.

[Chev R]

Hi Kiwi thanks for the input think what you saying makes sense. Just need to sort the spark break now and then back to Dyno. Thanks again

 

[KiwiRS4T]

Most common cause of spark failure is dead coils. If they are the originals they are due for replacement with new OEM or Splitfires (not cheap rubbish replacements).

[Chev R]

Hi Kiwi I've been busy with converting a set of coils but came across another thread discussing some of the issues other guys are having. After reading through It seems to me that I may have a similar problem. So I removed all the coils including the aluminum portion that is bolted in the middle of the cylinder head. Low and behold the hole bottom of the aluminum casing is black seems that the coils have been earthing against it when ever it spark breaks. So my car starts normal idles normal and rev up to limit when stationery also is not missing like a dead plug or coil. Only time it spark breaks it under load. So I got some liquid electrical tape with a brush and also bought some plastidip spray also for electrical insulation. I will be spraying the aluminum cover with that to insulate it so the coils does not spark against it. Also will do the coils and suppressors with the other. Worth the try I guess. I unfortunately cannot have the aluminum portion cnc'd out of plastic as the other guys did. So I will be doing that tonight possibly with put everything back tomorrow and go and test. Hopefully resolves my issue if not I have been busy with a set of other coils. Don't know if you've seen any of the threads speaking about spark break issues.

[Chev R]

Thought I'd add a video to show rev's clean only breaks up under load

VID-20170422-WA0003.mp4

[KiwiRS4T]

1 hour ago, Chev R said:

. Don't know if you've seen any of the threads speaking about spark break issues.

Yes there are hundreds of such threads. Your fix may work for a while (gap your plugs down to 0.8mm as well) but start saving for some new coils.

[Chev R]

Hi Kiwi plugs are gapped 0.8mm. I have a set of Bmw M3 coils that I will be using. Just will try and see what happens once this is done. Thanks for all the input I really appreciate it.