SsZERO

I had a few things done to my car, trying to keep it as well-rounded as possible with the budget I was working with. But obviously, my goal is maximum performance with relatively good driveability and reliability.

My engine work consists mainly of a TR cam with 110 LSA (not sure what exact specs are), comp cams 918 springs, harlan sharp rockers, asp underdrive pulley w/alternator pulley, ported/polished TB, mezziere electric water pump, hooker LTs, 3" off-road y-pipe into a dynomouth exhaust. The engine was dyno tuned and put out a max of 370 RWHP and 357 RWTQ (corrected). Good? Bad? So-so? Looking at the dyno sheet, the power curve seems to drop off steeply after its peak. Is that normal?

Since I just had this done, I haven't gotten it down to the track yet. On street tires, hoping for mid to low 12s. I don't know if 11s are possible. What do you guys think? + and - comments requested.

darknight

It all depends on the specs of the cam really. If you have a fairly small cam then the numbers seem decent. If you are running a 228/228 589 then something aint right. I wouldn't base much on dyno numbers though, they can be deceptive. Just get it to the track and see what it does. If you can get a 1.8? 60ft time, I can see mid 12's depending on weather of course. I bet the car feels a lot stronger by the sotp meter, huh. Good luck!

SsZERO

OK, did some digging and found the box from my cam. It is a Thunder Racing custom "reverse split" part number: 99-230/224-111

Specs are as follows:
230/224 .575/.563 111 LSA

Yeah, it looks pretty crappy since they're saying I should be at least around 400 RWHP. I am using 1.8 rockers, so could that be the problem?

When I first put this cam in, before tuning, I was actually making LESS HP than stock. I think something is up. My car made around 320/330 HP/TQ stock at the wheels. After these mods when in, my engine ran really bad. The baseline dyno was 300 RWHP and 290 RWTQ.

I really feel like something is missing, or is not correct...I should be putting out more HP and TQ, and my curve should not be as crappy as it is. Look at the dyno sheet I posted, my peak HP happens at 5000 RPM then plummets like a ricer after that. I want my peak HP around 6500-7000 RPM, and according to Thunder Racing, this cam should be pulling well after the 5000 RPM point.

SsZERO

Yes, I was on a dynojet at East Side Performance. They are a sponsor, and supposed to be really good. People claim they dyno lower there, but there are a lot of things that can affect dyno numbers.

While I do think that the 370/350 numbers are low, even for East Side's dyno, my main concern is the power band. It should not be plummetting like that after 5K RPM. The car feels awesome till about 5K, then it just dies.

jrp

iTrader: (16)

well one problem is USING THE 1.8 ROCKERS. with the rockers your looking at 232/226 duration and .609/.596 and more overlap @ the valve. the lobes are too agreesssive to accelerate them even more by using higher ratio rockers, TR clearly states this on there website as do most other cam manufactures. i'd say your valvetrain isnt up to snuff to handle the cam and 1.8 rockers. go back to the stock rockers and redyno.

darknight

I still don't get why you say the power drops off at 5K, the graph shows hp rising untill the pull ends at 6300?

dug

iTrader: (10)

Yeah, I dont know about using those rockers. Thats a lot of lift for 918 springs.

jrp

iTrader: (16)

thats another thing, the pull ends to early, should of gone at least to 6600. the 230 makes its best power there.

i still say its valvetrain issues.

JL ws-6

iTrader: (50)

I'd pull those rockers off, you could be seeing float at around 5K. The power dropping off like that is a definate sign of valve float. 918 springs are a good spring, but nor for over 600 lift. You also should have it pulled to 6600. Id take that advise, pull the rockers and try it again. Eastside does know their stuff, did you talk to Ken while you were there, what did he have to say about it? I'm sure that he can steer you in the right direction as to the possible fix's to the problems you are seeing.

SsZERO

I did make a mistake; I was looking at the TQ curve instead of the HP curve. Good thing they used such contrasting colors for the graph.

Anyway, I still think I should be making more power with this cam. I do have 1.7 HS rockers, confirmed that today. Still think it is valve float? I also wonder why I am making less TQ than HP. Usually its the other way around, isn't it?

BADSZ28

iTrader: (39)

Not when you go to long durration cams. As you start widenning the durration you sacrifice torque for higher HP.

DD966

iTrader: (3)

Hey, if you get to the track with those street tires and get low 12's will you PM me how you did it? Our numbers are close, and I'd like to know how to get into the 12's with street tires, given this much hp & tq. Thanks

SsZERO

Ah, that sucks. I guess everything is a compromise with performance. Is it worthwhile to build the LS1 into a stroker to regain some torque, or would it be better to go the FI route? Let me rephrase that; which way would be more reliable, since I do drive my car on the street several times per week.

DD996:

I might be going to the track tomorrow, weather and time permitting. If I break into 12s at all, I'll consider it worthwhile.