Let down on the Dyno!

[jrb1449]

Sorry for the confusion. I understand that all dynos produce different numbers (some higher, some lower) I really don't care about that at this point. The only reason I am thinking of dynoing elsewhere is simply because the shop that I just went to is 70miles from home. My old shop is like 10 minutes from my house and I will mostly likely et a price break since I use to work there!

 

So If I get a baseline at the new place and continue to go there from now on.

[Pyro]

94 mph trap with a 2700 pound car takes 175hp

 

97.5 mph trap with a 2700 pound car takes 195hp.

 

stock gearing is a 3.36.

 

old fuelie heads need about 38 total timing. rev it up to 4500 and set the max timing to 38 without the vacuum advance connected.

 

what valve springs are in the head? diameter? installed height pounds? pounds at 0.500" lift?

 

195hp @ 4500rpm at the wheels is about 235hp at the crank, which is about right for an almost stock cam. what is the engine vacuum at idle? this is an indicator of the cam size.

 

The first thing I would add is a 268H compcam and install a 2400-2600 stall. Then install some better heads, rpm intake, and a holley 3310 750. a 280H or 292H compcam to make max power, but a 3000 stall and a 3.90 gear would be required with the bigger cams.

 

a compcam 268H with a 2400 stall should get you to 275hp (220hp at the wheels), which should net a 102mph trap speed which is good for a very low 13. add some better heads and add another 30hp and trap at 105 which should be good for a 12 with good traction.

 

 

A T5 would be a nice upgrade but shift it slow.

[jrb1449]

Thank you very much! This is the kind of information i was looking for.

 

I currently have a 2600 stall and was already looking at the Comp 268H! I also have been looking into 750 carbs. I am not really sure what kind of heads to get. The internet is so opionated I find all kinds of discussions on which are better. They however, talk actual dyno results.

 

I may have to switch out my rear end. I already plan on the T5 swap ASAP.

[John Scott]

Dynos are great to get ballpark tuned, but so much changes on a hot track, hood closed, wind resistance, etc. etc. IMO, Better yet tune at the track. The faster the mph, the more hp you are putting down.

Timeslips > dyno sheets. You are actually doing what the car is designed for, not strapped to rollers with a big fan blowing on it. Dyno's can't help much tuning the carb for launch, 60'.

 

195 whp equates to about 96 mph in a 2750 lb car.

[Pyro]

my 240 would trap at 120mph (11.7 et) with a 11.1 cr 350 (362 cid) with 200cc dart iron eagles, compcam 292H, long tube headers, dual 2-1/2 exhaust, T5, 3.90 r200, hei with msd conversion, rpm intake, holley 3310 750. then would trap at 135 with a 250 shot of N02 added to that (10.7 et).

 

but when I first took it to the track it ran a 12.7 at 110 using a 11.1 cr 350 (362 cid), ported fuelie heads, compcam 292h, shorty headers, hei ignition, rpm intake, 3310 holley, single 2-1/2 exhaust, T5, 3.90.

 

The car picked up speed and lower the et over a few years of modifications. good heads and the long tube headers with dual exhaust really made big changes.

 

enough power to trap at 120 is about the max the stock axles and R200 can take.

 

If I had to do it all over again, I would had left the car in the condition I took it to the track for the very first time. it got too crazy, broke too often, and became a trailer queen.

 

if you want to drive it daily, then a 3.54 gear and a T5 will work nicely. A set of edelbrock performer heads, a regular edelbrock rpm intake (not air gap), a compcam 268h or 270h is good enough, and a holley 750. should be able to get into the 12's with good traction (new tires). not the worlds fastest car, but a fun daily driver.

[jrb1449]

if you want to drive it daily, then a 3.54 gear and a T5 will work nicely. A set of edelbrock performer heads, a regular edelbrock rpm intake (not air gap), a compcam 268h or 270h is good enough, and a holley 750. should be able to get into the 12's with good traction (new tires). not the worlds fastest car, but a fun daily driver.

 

That is exactly what I am looking for! a fast DD.

 

The only problem is the 11:1 compression. Here in Cali the highest octane I normally see is 92. Were you running race fuel or 100 octane with your setup? Is that really a good idea for a DD? I am fairly sure I have stock pistons of some sort in the motor currently.

[Pyro]

if the cam is big enough then 11:1 cr isn't a problem with 93 octane. a 292H with run with pump gas and 11:1 cr in a z (light load).

 

with 91 octane.........If you are going to run a 268H then stop at 9.5:1 with iron heads and 10:1 with aluminum. or 9.75:1 with iron and 10.25:1 with alum with the 270H, or 10.0 w/fe and 10.5w/al with the 280H.

 

The 280H would need a 3.90 gear and a T5 and would be fairly streetable. a 292 is a little lopey for a daily driver. you could even get a 280H cam and have comp grind it on 112 or 114 lsa to smooth out the idle, extend the power band, and drop cylinder pressure. they do custom grinds for an extra $50. good heads do well with wider lsa, due to good intake flow.

 

dynamic compression ratio is what you need to be concerned about. This is mainly determined by the static compression ratio and the intake closing point (cam timing events).