Jump to content
SAU Community

Recommended Posts

A thread for those with Ported heads.

I am keen to know what figures in CFM you are getting from both intake and exhaust ports.

Hopefully there are enough people on here with ported heads to keep this going.

So follow this proformer thingo :P

Head Type: (eg RB20DET, RB26DETT etc)

Porting Type: (eg CNC, backyeard job, Pro head guy etc)

Valve size: (eg standard, 1mm over size etc)

Flow at x lift: (eg 200cfm at .450thou or 130cfm at 8mm etc)

Manifolds fitted: (eg none, stock exhaust manifold etc)

Power/turbo/boost: (eg 300rwks, GT3076, 18psi etc)

Comments:

Port Photos: (Not asking to give away any secrets or anything like that)

Cheers

Andrew

Link to comment
https://www.sau.com.au/forums/topic/345389-head-flow-figures/
Share on other sites

Head Type: Cast Iron Ford Cleveland 2V (small port)

Porting Type: Cleaned up/Port matched by me

Valve size: Standard 2.04" Intake 1.56" Exhaust

Flow at x lift:Intake 197cfm at .450", 203cfm at .550" (tells me there is no point going any larger than 500thou lift) 175cfm Exhaust at .500" (flows a little more at .550 but like the intake its not worth going that big)

Manifolds fitted: None

Power/turbo/boost: Will flow just under 400hp at the crank

Comments: Pretty good for near standard heads with un-touched chambers, Has cemented my decicion to run it at 309 cubic inches instead of 351 or 383, due to the fact that the bigger capacity will cause I big drop off in power in the top end, as well as limiting revs.

Port Photos: To come

Cool idea :P

I don't have all the specs on mine though but will still add.

Head Type: RB25DET

Porting Type: Lewis Engines (Adelaide)

Valve size: Standard

Flow at x lift: 265cfm at .400 on intake

Manifolds fitted: Stock exhaust manifold and stock intake runners (Plazmaman plenum)

Power/turbo/boost: Last dyno tune on old Microtech 263rwkw on BP98 at 18-20psi on HKS GT-RS

Comments: Head was ported, polished and had the valve seats cut by Lewis Engines. Installed all new valvetrain gear along with Performance valve springs and Tomei 256 camshafts.

On the road difference, very large gain in midrange power, not much gain in peak kw figure due to limit of HKS GT-RS.

Currently retuning it myself and will have new dyno sheet next year.

Edited by PM-R33

Yeah we got very good results out of it :P

Normally he ports them out to around 250cfm but my head was with him for a long time so he spent a bit more time on it and went a bit beyond to what he normally goes for the price I was charged.

Cool :P

Heavily ported 2v cleveland heads will flow about 260-270cfm, Interesting when you consider the RB head has 4 valves per cylinder and is 30 years newer than the Cleveland. They were designed for a 5.8L v8 though compared to a 2.5L turbo six

You forgot to add

What car is used for: Street/Drag/Track

Very important in port selection. And 265cfm is nothing for an RB25 head. We have made 480hp at the wheels on a stock head with pon cams.

I'll try to get more information on flow etc for Noels head if Marty White will give them to us.

It is also important that the flow specs are checked properly. Some people incorrectly check flow at the cylinder head face. 2 inches of tube should be added on the exhaust side to get correct flow on an RB cylinder head

And 265cfm is nothing for an RB25 head. We have made 480hp at the wheels on a stock head with pon cams.

Ohh I didn't mean it to sound like it was a huge amount or something, I know you can get a lot more :P

It's a street car and the porting was only done since the head was off to get the valve springs put in. Figured while it was off to give it a bit of a port.

Edited by PM-R33
Ohh I didn't mean it to sound like it was a huge amount or something, I know you can get a lot more :P

It's a street car and the porting was only done since the head was off to get the valve springs put in. Figured while it was off to give it a bit of a port.

nah I know, was moreso replying to what Zebra said

  • 1 year later...

Rb25

Pro head guy

Standard size ferrea valves

234 at .500 before porting

245.5 at .400 intake after

253.3 at .500 intake after

135 at .300 exhaust before

137 at .500 exhaust before

157.7 at .300 after

161.6 at .500 after

No manifolds

Ss2 hypergear will be fitted

Mostly street with occasional track work

Most of the work done was on the chambers with 4-5 hours done on the ports. Will try get photos up later. Also tomei springs and poncams fitted

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
    • For race cars, this is one part where I find having the roll cage bar having gone through a hole in the floor better than the build it up on a ledge inside... The Merc I help on, the main hoop ends are marked on the car, and the jack is marked... Jack goes under a few inches and lifts one whole side of the car up... Removes that fight for long slim jacks for race car duties!   My biggest issue for the daily drivers I work on, is my jacks don't go high enough. The jacks start out on a few blocks, jack it up, then start a second jack under it on more blocks, and then I can get an axle stand under it. My axle stands are presently in use, and are nearly fully extended. The car is sitting with barely more than a cm of clearance to get the wheel off the studs! Sarah's Kluger is the same, as it has an ungodly amount of droop available in the suspension and a distinct lack of good jacking points!
    • Happy? Yep, my to do list is getting shorter and shorter. Either this light approaching is the end of the tunnel, or I'm about to be hit by a train... Ha ha ha   Also, Duncan isn't that far out of town that you need to make a multi day drive out of it. 😛
    • Sorry I meant that we are building the EH for a client.
    • LOL, when one "money pit" is never enough Noice, and excellent work mate
×
×
  • Create New...