do you have to run an intercooler when turbo or superchring?

[californiacuda]

Do you have the numbers after switching to the turbo system, you should pick up another 100 if you make the same boost. The supercharger parasitic loss is substantial(as you probably already know).

[64duece]

No specific comparison was made due to the difference in direction after we went with the 90mm and then 98mm turbo.

We swapped the 355" (4.030x3.48) short for a 374" short (4.125 x 3.5) due to the need for additional parts strength. We also switched to a water to air core aswell.

I will note: We used the same heads. Upgraded fuel system, intake and just abit more camshaft. With the intercooler air temps now in the 110* range, we now were making 1000hp using just 14lbs of boost. We followed that with higher boost levels, ultimatly reaching 28lbs making 1660hp with a tradional 23* head.

I've tested several superchargers back to back in efforts to see the parasitic losses. I can say, running a much larger than needed blower will "cost" you some power. We saw differences of nearly 100hp from using a unit that was "properly sized" and capable of producing required boost pressure vs one being "turned down" to the same pressure level. Also, the average power from the turbo was superior to any of the centrifiguals we tested.

[Blown353]

Thanks for the info Dennis. The bit about using a blower larger than needed and the additional power consumption is good to know, but makes sense being that you are probably working in an inefficient area of the compressor map when you use a blower that's too large for the job.

I hear you on maxing out a fuel pump, I'm eating about 510 lb/hr right now going by the injector duty cycle numbers. I had to add a Boost-A-Pump to keep up as I was right at the edge of maxing my SX pump out.

Non-intercooled with the EFI my setup would only tolerate about 22 degrees max timing. It used to tolerate 27 degrees with the carburetor but after switching to the tunnel-ram style EFI manifold I had to take a lot of timing out of it. I haven't tried putting any more timing to it with the intercooler but that's on the agenda for this week. The only thing I don't like is I have no way of noticing detonation except for checking the plugs-- the engine & supercharger are just too loud to hear anything except severe detonation over, and if I can hear that it's too late. Any suggestions? It's easier to pick up light detonation on a dyno as you can see the torque curve "bouncing around" but tuning for max power in the car makes me rather nervous as I have no reliable way to detect light detonation in real time, only an after-pass plug check.

[64duece]

No problem.

The timing #'s sound right. We were at 24* prior to adding an intercooler. I have a firend w/ a 406 SBC running upper 20's on pump gas with his blowthrough system.

You hit the nail on the head as for timing/detonation. My best advice is to stay conservative. Have a couple sets of NGK's on hand (we used 9's hot-air and 8's with cooler temps) and you should be able to read the ground strap. Pull all 8, keep a real close eye on the porcelean and sneak up on it. Tuning via mph is still a good process if you know your car and are willing to weather correct.

[Blown353]

Originally Posted by 64duece

You hit the nail on the head as for timing/detonation. My best advice is to stay conservative. Have a couple sets of NGK's on hand (we used 9's hot-air and 8's with cooler temps) and you should be able to read the ground strap. Pull all 8, keep a real close eye on the porcelean and sneak up on it. Tuning via mph is still a good process if you know your car and are willing to weather correct.

Thanks again Dennis.

Wow, those are cold plugs. I think I'm running BKR7ES plugs at the moment; I'm trying to balance street driving vs "beat on it" driving and the 7's seem to be OK; if I cruise the car lightly they look a little loaded up (even though I have the engine running quite lean at light loads) and if I beat on it then shut it down they look a little on the hot side but not scorching hot. Think I should go a little colder? I am running water injection so that is probably helping my plug choice quite a bit.

Still wishing an ion-sensing knock detection setup was cheaper than $20K or so.

[64duece]

Most of our stuff is pure race, not much idle cruize time I've run the 7's in the mid boost levels (10-14) and did have them in at 18lbs without "noting" problems but, I wanted to work out the timing without having a glow plug being a cause of problem. I played it safe and went to the 9's, they we're a little cold for sure. The 8's were fine, I was playing it safe.

I'll probably run 7's in my twin turbo 565 street beater. defiantly want to keep the plugs clean in there. It'll never see more than 12 to 14lbs and has water to air w/ heat exchanger.

[Diesel77]

To answer the question, no you dont need an IC to drive the car around and will make decent HP most of the time.