328i Sport track project - Cadwell June 09

Andy916 · Post by **Andy916** » Tue Mar 11, 2008 7:12 pm

The cheap Hankooks are pretty good, I've got them currently on my trackday wheels. Last time out at Cadwell the instructor commended their grip.

Just got the details through for Sunday ... in a class with a couple of Evos and a GT3RS amongst others

Andy

Tommy · Post by **Tommy** » Sat Mar 15, 2008 12:59 pm

Just got back from having the BBTB and modified inlet manifold fitted. I am quite literally astounded by the increase in power! It is more noticeable than my stripping of the weight - it's that much.

Here's some more detail about the modification:

The Bbtb/manifold conversion is designed to remove the restrictions that BMW deliberately built into the M52 2.8 engine. They did this to restrict the power to 193 bhp (the same bhp as the old 2.5 unit). The reason for the restriction is the German insurance market, which penalises cars which have more than 194 bhp. However, the 2.8 has a much better torque figure than the 2.5 unit.

Power gains with a free flow filter are in the region of 20 -25bhp, typically giving around 218bhp on a 328. Tests show that the manifold will flow 275 cfm of air as opposed to the standard 185cfm!

The manifold itself is an extensively re worked second hand M50 manifold. The modified manifold has a new custom made chamber, screwed and bonded into the underside, which houses the idle valve, air sensor, and oil recirculation valve in exactly the same position as the original M52 manifold.

Also in the kit is a big bore throttle body.

When I saw the difference in the parts, all was plain to see. The intake ports on the engine are around 30% bigger than the ports on the original manifold. However, the new manifold matches the engine ports perfectly. Looking at the runners, the new manifold runners are nearly twice the width of the original. Finally, the TB has been bored an extra 3mm to give around 15% more surface area.

I thought the power would only be realised in the upper regions of the rev range but it's actually across the board. The bum dyno notices the increased low down power more but that's not to say the top end isn't different. It just continues to pull to the redline whereas before it flattened off at around 4500rpm. It's not unlike the ATR in delivery - just not as long lasting.

I have never known such a powerful modification for the amount of money (

Post by **Stuart** » Sat Mar 15, 2008 1:55 pm

Sounds like a great modification and good value too.............................you know you're gonna need to dyno that now though

Seeing your car and Sideways for comparison should do the trick at Cadwell. Will do my very best to get there for that :thumb:

Tommy · Post by **Tommy** » Sat Mar 15, 2008 2:10 pm

Bum dyno will do for now. Will have the car dyno'd after a remap which will be later in the year.

As for comparing with Jason's car, it's going to be interesting since we're not running track tyres, will have two people in the car AND have an extra 100 kgs disadvantage!

Post by **Stuart** » Sat Mar 15, 2008 4:46 pm

Ok so maybe a comparison won't work after all. I'm sure you'll have fun anyway. I have found time and again that there is no direct correlation between the money invested, the speed and the fun you can have. The law of diminishing returns applies to cars so well and yet it's in our DNA to keep spending

Mr Fletcher · Post by **Mr Fletcher** » Sat Mar 15, 2008 4:59 pm

that sounds a good mod tommy i'm a little stuck with the 325 unless i fit a stroker kit or somthing else costing more than i really want to invest in the car . :roll: you may still be slightly heavier but you have a reasonable power advantage now

i'm running 181.6 bhp at the moment

cheers

jason

Tommy · Post by **Tommy** » Sat Mar 15, 2008 5:05 pm

We'll certainly have fun. Really can't wait for Friday

Post by **Stuart** » Sat Mar 15, 2008 5:10 pm

How tough does the 2.5 or 2.8 'feel'? I know this may be slightly premature for Tommy to answer.

Bladey and I were at Donny on Friday and we were discussing various durable and cheap cars that still had a bit of poke.

I don't really want to entertain another 20 year old car that will start to need structural work. I already have enough of them

Your feedback would be great.

Tommy · Post by **Tommy** » Sat Mar 15, 2008 5:10 pm

sidewaysfletch wrote:
i'm running 181.6 bhp at the moment

cheers

jason

I've just worked out bhp/ton. Jason, you are at 155. My car with two people and at an estimated 220 bhp is 163. It will definitely be interesting on track.

Mr Fletcher · Post by **Mr Fletcher** » Sat Mar 15, 2008 5:53 pm

stuart i think that it is about what people want from a car , i could of carried on using my bmw in a fairly standard form but i would of soon been fed up with its handling . all cars of a 20 year vintage have issues of some form which are well documented on the web, the e36 325 have had some problems with the rear diff carrier ripping the floor out , rear strut top mounts cracking,
cooling system issues, but once these areas have been checked or addressed then no problems, if i blow my standard engine up approx