My draw through turbo

[advinnie]

Hi all. The other day I got a BHP app yes I knew they aren't great but we have tried this app on three different cars where we have known the rear wheel BHP and the app was only out by 3hp on a 205 bhp 2.5 l V6 jag. The app needs to know total weight of car, length, width and drag coefficient and so on. Any way did some runs and was greatly disappointed with the out come, only managed to get a max of 79.1 BHP @ 73.4 mph at the rear wheels so did some more carb jetting and leaned the mains from 1.20's down to a pair of 1.10's and then dibe another run and got a reading of 98.7 @ 70.4 mph (rear wheel figures) still disappointed in this out come. I'm not Shaw how to convert power from the wheels to crankshaft power so if anyone knows how to do it can you let me know please

[Chip Birks]

Tall ones look cooler too!

[Clonebug]

My engine is 112 whp at 6.0 lbs boost.
133 lb./ft of torque

You are more than likely going to be less than that with your 1600 even at 8.0 lbs boost.

[advinnie]

Chip birks
Yes I agree tall rear and small fronts look cool.

Clonebug
I want more power

[petew]

Most of the great small sports cars from the 60s through the 80s had around 100fwhp and around 2000lb in weight. The combination is great for fun without being so fast it's unusable on back (B) roads. Enjoy what you have and get your car to handle. I'd also look into finding a local club you can do autotests or autokhanas with.

[advinnie]

[Clonebug]

You have a couple of options.....

Turn up the boost.....
Upgrade your fuel and ignition.....
Build a bigger engine....

All will do what you are looking for.

[advinnie]

Im back found out my wastegate was getting stuck so sorted that out today and did some more runs and I'm now getting reads of 132 bhp at the wheels. Couldn't believe this so tried the app in five friends cars and on the same stretch of road as I used for the bug and all the app readings where within 4 bhp of the manufacturers bhp at the wheels. If that's the case I'm well happy and using a GPS data positioning unit I got a 0-60 time of 5.47 seconds but only got a 0-82 mph time of 8.92 seconds
I really need to get this machine on a Dyno and get a print out cause I know you lot just will not believe me.

[advinnie]

Hi all I'm having a strange issue going on. The first sign something was not right was that I was getting random misfire so checked the plugs, cylinders 1&2 are a little sooty but the engine is a draw through turbo so it has to run a little rich, anyway checked plugs 3&4 and they were very sooty and basically stopped working. So cleaned them all up the other day and all was good no more misfire. I've now done around 100 to 150 miles on the cleaned plugs and today the misfire was back. Pulled the leads of the distributor cap one at a time and found the plug 3 was not always firing so pulled that plug and it was once again so sooty it was failing. So I decided to pull all four plugs and once again cylinders 1 & 2 where ok but plugs 3 & 4 where totally covered in black fluffy crap. So how the hell can cylinders 1&2 be fine and cylinders 3&4 run rich when they are all feed from one carb?
I've checked for air leaks believe me I have checked and found none. Any ideas at all?

[madmike]

Is you intake tube a 'Y' or a 'T' ? T style is better Y's tend to favor one side

[advinnie]

It's a "T" shape inlet manifold. Just thought of something, on the inlet manifold there is a pipe coming out of it that I had no use for and on the inlet manifold end piece that bolt to the head that also had a pipe on it that I had no use for so I connect the to pipes together so may be that could be the issue?
I've also just been offered £8,000 for the bug witch means if I sell it I could get my 2003 V8 GT Mustang but I don't know if I can part from it

[Dan Dryden]

Have you compression tested? Leak down test? Are the valves sealing correctly?
Did you just clean off the spark plugs again? Once they’re fouled, they’re never quite the same. Try renewing the plugs first. The fouling could have happened when you were trying different jets etc.

[advinnie]

Compression check can in as follows
Cylinder 1 - 112 psi
Cylinder 2- 110 psi
Cylinder 3 - 113 psi
Cylinder 4 - 110 psi
Yes I just cleaned the plugs and put them back in.
I thought I had found the perfect jetting but I started getting detonation the second I hit six psi of boost. The idle jet ( .45 F8 ) are great the engine loves them and there no black smoke when you floor it, but move up to even a .50 idle jet and she will load up at idle and puff black smoke out the exhaust every time you touch the throttle. The engine loves 1.10 mains she really does but I can only go to 5 psi boost safely cause if I hit six I get detonation. Also i had dropped the venturis down from 28 to 24 mm witch help massively with throttle response and stopped the engine stumbling when manifold pressure hit 101Kpa but when on boost the engine just didn't fill right.
I'm now trying a strange combination of jets.
Now in one barrel I have
a small 24mm ventrui
45 F8 idle
1 35 main
1.70 air correction
.45 pump jets

And in the other I have
28mm venturi
50 f8's idle
1.60 main
1.70 air correction ( to help richen her up at the higher rpm range)
.45 pump jets

With the combination there is no black smoke when I boot it but think the pump jets need upping. But at between 2200-2500 rpm she runs mega rich and thus is the point that the idles, progression and mains are all running together so need to figure out how to the mains kicking in so early.

[Dan Dryden]

I’m really no expert when it comes to tuning, but I have read my copy of Turbomania a few times.
I’m a little rusty on the details but I’m sure they modified the emulsion tubes in order to use the “correct” main jets without it leaning out.
Maybe this is something you could research into?

[advinnie]

I will look into that. Cheers