150-160whp OEM avgas extraktor grenrör?

[Ruben]

Hi,

Excuse my English.
I was wondering at what power levels the stock/OEM exhaust manifold is becoming a limitation?
I've heard some Swedish VOC cars get 170-180 hp (crank) with the standard manifold but better downpipe and exhaust.

I'm trying to figure out if I really need to spend a lot of money and buy an extraktor grenrör for a 150-160WHP engine.

Car is a V360 I can only get the Timos motor grenrör which is quite expensive when you ad shipping. The stock downpipe is pretty crappy on a 360. Very twisted, small runners.

Engine will be something like this:
B230
11.0:1 CR
Thin head gasket for tight squish
Max RPM 6500-6800
Ported head, maybe with bigger valves if needed
kam, not sure yet. Maybe a Jens G special? Manen 7 or maybe a K with the low rev limiter?

Extended exhaust duration (split timed / dual pattern) camshafts are recommended for LPG (square timed work well in some performance 4 & 6 cylinders) .

B21F/B230E intake
2.5" exhaust system
Stock manifold with different downpipe or timos motor grenrör

Fuel:
LPG and E85

Managament system:LH2.4 or MS

So my question is: Is the better manifold going to make a big difference? Should I keep the money in my pocket and have a better head made?

Is my HP idea realistic with the low rev limiter of 6500/6800rpm? (LPG and high revs don't go together very well and the tight squish limits it also)

MVH
Ruben

[Ruben]

No one?

[fredde_vit_pv]

most engines with silly exhaust manifolds gains both hp
and less fuelconsumtion!. cams like "månen7" do not like
crappy exhaust so a extractor is probably a good investment
in that case!,it makes furder uppgrades possible anyvay!
(maybe the stock LH2.4 is a issue!?)

/F

[Amders]

Theres bigg There’s big difference on tubedimensions on org frontexhaust and the VOC frontexhaust.
You can try make one frontexhaust by yourself and test.

[Erland Cox]

If you are using the stock manifold and down pipe together with a 2,5" exhaust all you have to change is the collector pipe to 2,5" and it will work fine. I think there is a finished down pipe from Simons that already is like that but that is for a 240 and 740.

Erland.

[Jens Gustavsson]

meny voc cars run the 242GT down pipe (bigger dim) not to hard to make you self)

it is ok if the cam is not to big (som fredde säger)


voc cars = H cams 240deg intake 235 ex/1.25mm/108

a cam = 222 deg

M cam 204deg

måne 7 = 269 deg (it is a low lift semi/full race cam like my STS269 or NH164 mm)

STS 247 =247deg and it is max whiteout extraktor hedders.

[G-son]

Någon som har jämförelser på effekt med originalgrenrör vs. extraktor på någon sug-rödblock? Vore intressant att se, och ganska matnyttigt för att avgöra när extraktorröret är värt vad det kostar.

[Erland Cox]

Dom flesta köpe extraktorrör är ändå så fel att det nog inte blir nån större skillnad jämfört med om man fixar till sekundärdelen till nåt så när rätt mått. Jag har originalfgrenrör på min B20 nu och 2:an och 3:an på dom rören är siames vilket inte är optimalt. Jag ska bromsa längre fram och kan testa skillnaden mot ett extraktorrör då.

Erland.

[Karl V]

Erland: När du säger "fixar till sekundärdelen till nåt så när rätt mått" menar du då längd eller diameter?
Vad bör vara rätt diameter och längd?

Är det lönt att ha större diameter än de hålen som kommer ut ur det gjutna grenröret?

/Karl

[Pacman]

To further push the thread question....
The two single most important parts to gain power is the engine management system and the camshaft. Next is a porting job on the cylinder head.
That and a better downpipe and a bigger exhaust system and youre good to go.

Like Erland says, most premade go-fast extractor headers to B230 is poorly better than stock+better downpipe. To really enjoy the benefits of a extractor header you should get one tailormade for your engine.

Out of stock intake manifolds, the K-jet one is the best. However it has not bungs for injectors so those has to be welded on.
The B230F intake is tempting easy to use, but is is a major limitation of flow and thus power.

[JE Jr]

Dom flesta köpe extraktorrör är ändå så fel att det nog inte blir nån större skillnad jämfört med om man fixar till sekundärdelen till nåt så när rätt mått.
Erland.

Yes, feels like that. I have a KG/Timo Phase1 header on my 740. B230E K-Jet with K-cam and Simons 2.5". I couldn't feel any change at all after installing it. I think it maybe even went slightly worse?

[KLR142]

I also have the Phase1 header on my 240 but had the secondaries shortened to better match the H cam according to Pipemax(or some other program that Jonathan at RSI used). My car doesn't make much power though(~138whp/148wtrq), considering the 10.8:1 compression ratio and head flow(RSI stage 2 with 46/38 valves, ~200cfm on the intake ports and up to 166cfm on the exhaust). I still have the LH2.4 intake manifold though and am having injector bungs added to a k-jet manifold as my next project.

After that, I'll either put a stock exhaust manifold and modified downpipe on(2.5" collector) like I used to have, or get a larger camshaft and custom exhaust manifold made.