Just had my 96 Dynoed for the 2nd time, first time since the twins have been installed. Previously with the mods in my sig I dynoed 375hp, 885tq on Dave Dunbar's dyno. Last week I dynoed with the same mods except for the addition of twins. My results were 345hp, and 791tq what gives? How can I have less power yet be burning every bit of fuel I am injecting? Previously on the stock turbo I would never clear up the smoke, now with the twins I don't have any smoke at max power. Plus the seat of the pants dyno tells me that the truck is alot quicker now than before.
Now for a little explanation: The dyno was a mustang dyno and it was done at a little import shop, they offered for free. They did not have that sensor to read rpm, insted I had to hold the truck at a certain mph and read off my rpm so they could attempt to calibrate their dyno. That doesn't seem entirely accurate in a way of reading power?
My torque and hp readings both maxxed at about 2100rpm and the horsepower stayed flat from that point to redline, does that seem right? I would have thought hp would continue to climb until redline? Or fuel cutoff?

 

I'd go and find another dyno. Also, mustangs usually tend to read lower than normal. As far as the curve goes, mine peaks at 2200 and stays dang near flat until 3100.

 

Mine was done on a mustang dyno ... and calibrated in the same way ... and the numbers were very consistant .... holding at a specific RPM is a very accurate way of calibrating the dyno. Do you have a lockup switch, or is the TQ unlocking on the dyno ? ... that's a problem i had, after about 20 pulls i finally got it pretty good but i definitly will be installing a lockup switch before my next dyno run. I learned the hard and expensive way that the dyno operator and configuration of the dyno is of the utmost importance. I would trust dave's dyno i've heard nothing but good things about his setup.

I have also heard that mustangs read low, but i felt it read my truck a little high.

Maybe it's time to tune your truck ? .... how were EGT's this run? Maybe you are ready for more fuel, 370's w/ no DV's on twins just aren't enough fuel ... time for some DDP5's or mach 6's

What twins setup?

 

The twins use my stock turbo and a BHT3E with a 23cm exhaust housing. I know it's a little small but I started to piece it together before I really knew what exactly I needed.
What do you mean by tune the truck? I did the timming on it a little over a year ago and set the valves.
EGTs were around 1100-1200. Even on the road I can barely get it over 1200 unless I'm towing something and put it to the floor. My thought was fuel too, I figured the 370s weren't enough to feed the twins, I think I'm gonna get some laser cuts soon. Like I said under wide open throttle all you see is heat waves comming out of the exhaust, not any smoke at all.

 

my twins are almost the same with the tst on 5 and smarty maxed the smoke clears up really nice.

 

What boost #s did you see?
Perhaps you have a boost leak in the new piping.
I have a similar set-up but I use a 3B with the 26cm housing,215pump with a #10 plate and stock 215 injectors and can hit 57-58psi

 

I was hitting 49psi, I have the wastegate set right around there as I only have studs and not a good head gasket, I thought anything much over 50psi would put a hurtin on a stock headgasket even if it had studs?

 

I would not get too upset...two different type dynos....two different readings. Dynos are like oil analysis; people use them for absolute readings when there true purpose is to read trends or differences!

I was told adding twins (even after a big single) would gain 50-60 hp. I gained 56 hp. Go back to Dunbars for true reading of difference from previous set up.

The only type dyno I've seen give fairly consistant readings at different shops is the Dynojet 248C, but whenever possible... best to stay with same shop/dyno for reading results from changes made.

RJ