4AGE ITB's Rolling Road session

Posted: Sun Oct 07, 2007 1:01 pm Post subject: 4AGE ITB's Rolling Road session

I have just been to the rolling road with my MG Midget with 4AGE, It is standard apart from the AE101 ITB's with T3 manifold. I am also running a Perfectpower standalone ECU. The car standard made 118.6 @ 6500rpm, the car with the ITB's made 177.7 @ 7200rpm on the first run yesterday.

The can ended up with 129.1bhp @ 7600rpm.

I will post the powercurve when I get it scanned in. So only gained about 12hp from the upgrade, but the car feels alot stronger in the mid range. Only running about 30 degress advance at high rev/high throttle, didn't make any more power by advancing any more. My exhausrt manifold is home made and I think restrictive, plus my car smokes heavily at the top of the revs, changing gear. So happy enough. Will also post some vids.

Ivan

Posted: Sun Oct 07, 2007 3:11 pm Post subject:

177?

You mean 117 I hope. Otherwise you lost a lot there... Puh

Posted: Sun Oct 07, 2007 6:29 pm Post subject:

Yes, sorry 117, think 177 was a bit on the optimistic side.

Ivan

Posted: Mon Oct 08, 2007 9:38 am Post subject:

Would be interested to know what injectors you are using, and what you have done about a vacuum tank.

Posted: Mon Oct 08, 2007 10:06 pm Post subject:

I have attached the dyno below. I have made a temp vacuum reservoir using a in-line fuel filter. I have another one bought from goldeneagle in the states, haven't got round to fitting it yet. I have retained the standard fuel rail, injectors etc.

The figures don't look that impressive but the car drive alot be low down and mid range.

Cheers

Ivan

Posted: Mon Oct 08, 2007 10:33 pm Post subject:

Why did the first run end at 7250rpm? Doesn't look like the engine made much hp in the later rpms..certainly considering that little shimmy that made the engine make the peak hp figure. Realistically, it looks more like 120hp and a torque curve that doesn't resemble the std 4A-GE item. You could probably tune it to make more peak hp in a narrow band, but with a light car and the torque curve you have now it probably wont be any more fun then it is now. Looks like an engine thats nice to drive.

Posted: Tue Oct 09, 2007 5:16 am Post subject:

By standard injectors I presume you mean standard 16 valve ones? Depending on which colour injector you have, potentially some big gains possible there. Plus of course you could go pretty silly with some cams and still retain some good mid range torque.

You have a standalone so you could really go for it.

Posted: Tue Oct 09, 2007 9:10 am Post subject:

Why would big gains be available with other injectors? 120hp is well within the range that can be handled by the stock units and there is not much wrong with their spray pattern.

Posted: Tue Oct 09, 2007 10:32 am Post subject:

without any head work (porting or other cams) I don't see the gain in using itb.

Wataru Joined: 11 Jul 2006 Posts: 51 Location: Netherlands

Nice car Ivan ! ( please post a pic Wink

of your setup) I assume the dyno read out you posted is crank horsepower ?
129 Hp is not a bad figure. Driveability must be good if I look at the graph ? weight of the car ?
I drive a fisher fury with small port 4 age and stand alone ecu, throttle bodies form a suzuki gsxr ( 48mm I believe ) and custom made exhaust manifold giving 139 hp at the flyweel. I use 280cc injectors ( do not know which type as they came with the car ) and a sard FPR ( which is not fully functionable since I have to connect the vacuum union to the airbox later ).

I am still working on an airbox as I am using a pipercross box filter which sucks hot air Neutral

. After the airbox is finished and I have some velocity stacks I will have the car dynood and the ecu callibrated by Ron ( If you read this Ron it will take some more weeks to get everything finished ).
car weight ( wet incl fuel & tools ) 560Kg. Weight ditribution 50/50.

anyway this is my baby :

AE86 : Technical > 4AGE ITBs Rolling Road session

AE86 : Technical > 4AGE ITBs Rolling Road session

Posted: Tue Oct 09, 2007 11:11 am Post subject:

I agree about the injectors, they wouldn't make any difference, we tried richening the mixture at the top end but it made no effect on power. I think the main problen is the engine is tired and very, very smokey at high revs. And also because the engine is in a MG midget the exhaust manifold is very restrictive, 4-2-1 all before it exits under the car, with tight 90 degree bends, this is the only way it can fit in the car. So I am happy enough, probably most impressive is mid range 4000-6000rpm. I use the car for autotesting so this suits me fine. I am going to an event on sat so will hopefully put some vids on youtube.

Ivan

Wataru Joined: 11 Jul 2006 Posts: 51 Location: Netherlands

good luck on the event.

Posted: Tue Oct 09, 2007 3:26 pm Post subject:

Joined: 12 Jan 2008 Posts: 1

Parrot,

No offense,but if you'll look at Ivan's dyno sheet,you'll see he has more than enough fuel flow to support his power output.His A/F ratio trace is rock steady,and between approximately 13:1 and 12:1 as rpm increase.If anything,he might even want to lean it out a bit!Any richer and he would most likely begin to lose power.As was mentioned earlier,higher-flowing injectors are only needed if airflow into the engine warrants it(via porting and more aggresive cams,like the GrpA engine you mentioned above).