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| JonnyAngle | HP estimate | ||
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Senior Guru
 
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On my 86...
If I go with the AFR 195cc heads and a cam with 216 223 duration and .499 .493 lift, 1.6 roller rockers, LT headers and tune. I estimate about 300 rwhp? Then if I get a new intake, I am guessing 350. Does this sound about right? |
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Posted on: 2008/8/18 15:27
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When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car. 
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| jsup | Re: HP estimate | ||
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Elite Guru
 
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1. why would you do all that and not do an intake? ( I happen to know where there's a beautiful SR for sale that would be perfect for ya)
2. Those heads are too big. Also, the cam isn't crazy if it were me I'd be looking at a set of Patriot or Brodix or TFS, put some cash back in your pocket. You need 180CC heads, no more. 3. I'd pick an intake before I piked the cam, that's just me..or at least at the same time. But yes, with those mods, or similar ones, you'll see 300 at the wheels if you do it right. How do you drive the car, start there. If it's a street car and you're not winding it up to 7000 RPMs on the regular basis, a Miniram, which I'm pretty sure will be the "intake" you're looking at if history serves, and big cam probably won't do what you want. ESPECIALLY with 195 heads that flow at high lifts. |
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Posted on: 2008/8/18 16:03
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Parts don't make power, engines make power. |
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| JonnyAngle | Re: HP estimate | ||
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Senior Guru
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Well I don't have all of the money to do all of it at once. IT is a daily driver, so you're right, I don't need a wicked cam. However, I would like more HP than the "average DD."
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Posted on: 2008/8/18 17:19
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When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
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| FATED | Re: HP estimate | ||
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Guru Newb
 
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http://www.lt1intake.com/services.htm
If you want to go on the cheep, check the above website for modifying an LT1 intake. I did one for about $200 total. Lunati has a 220/228 Voodoo cam for about $120. Keep your heads, replace valves with swirl polished valves and get the correct springs for the above cam. This can keep you busy for a few weeks but you will get 350 HP with a low budget. Chip tune, raise the idle 100 rpm. Do a little porting, gasket match and take a little out of the bowl areas. Get a book on porting. |
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Posted on: 2008/8/18 18:48
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1985, Performance Chip, hole in muffler, and other Mods 
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| cuisinartvette | Re: HP estimate | ||
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Elite Guru
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180 head is more than enough. Are you planning on changing intakes down the road?
Different point of view on porting, if you havent done it have a pro do it. There is so much more to it than people think. |
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Posted on: 2008/8/18 19:14
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| JonnyAngle | Re: HP estimate | ||
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Senior Guru
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Quote:
Yes, I will change intakes at some point. I'm not a a budget where I can drop $5k at once, but more like $1500 a year for the next 3 to 4 years. As far as porting, I don't have a mneumatic dremel anyway, so the only option available to me would be a file... and that ain't happening. |
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Posted on: 2008/8/18 19:58
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When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
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| jsup | Re: HP estimate | ||
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Elite Guru
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Quote:
Yep. 350 at the crank. Not at the wheels. The stock heads are good for about that... |
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Posted on: 2008/8/18 20:01
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| JonnyAngle | Re: HP estimate | ||
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Senior Guru
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I like the new BBK that's allegedly going to be released for the market. Thanks for the help dudes. So say I have 350 at crank, that would equate to roughly 320 at the rear wheels?
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Posted on: 2008/8/18 20:59
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| jsup | Re: HP estimate | ||
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Elite Guru
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Quote:
Figure 20% drivetrain loss, on the high side. 350 at the crank would be about 280 at the wheels. |
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Posted on: 2008/8/18 21:02
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| JonnyAngle | Re: HP estimate | ||
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Senior Guru
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dANG! so a stock 86 would only have 184 Hp at the rear wheels?
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Posted on: 2008/8/18 21:37
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| jsup | Re: HP estimate | ||
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Quote:
Basically, yes. |
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Posted on: 2008/8/19 0:19
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| Andrew | Re: HP estimate | ||
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2013 Memorial Day Car Show Winner!
 
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Jsup,
I have to humbly disagree with you. It is probably 20% at some point in the RPM / HP range, but I doubt it is 20% at it's peak. In other works, at 2500 rpm, if the motor makes 100 hp, 20% loss would be about 20 hp. Most of the parasitic loss of power has already taken place, so when the motor spins up to it's tq / hp match (5252 rpm) and it produces 300 hp, the parasitic loss may only be 30 hp, or 10%. I guess what I'm trying to say, but not doing it very well, the parasitic loss to the rear tires does not increase at the same rate that HP does, since power has already been used to start the spinning momentum. After seeing a few LT4's on the dyno, they produce about 295 - 300 rwhp stock and the factory claims 330 at the crank. Granted, the peak HP is higher in the rpm band than the L98, but the parasitic loss should be similar. My guess if motor produces in the 350 chp range, it would be more like 310 - 315. I believe 280 would be extremely conservative. All of this is just theory of course. Does this make since or am I just out in left field somewhere? One thing is for sure, if the motor produces 350 chp, you will definitely notice a difference over the stock rating!! |
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Posted on: 2008/8/19 1:17
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2003 Atomic Orange Z06 Sold - 1996 Competition Yellow LT4 - DRM 383, NX N2O, Line Lock, LT Headers, 3" stainless exhaust, Power Effects, and many more mods SOLD 1996 Competition Yellow LT4 SOLD 1979 4 Speed with 383 |
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| jsup | Re: HP estimate | ||
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Elite Guru
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[quote
Andrew wrote: Jsup, I have to humbly disagree with you. It is probably 20% at some point in the RPM / HP range, but I doubt it is 20% at it's peak. In other works, at 2500 rpm, if the motor makes 100 hp, 20% loss would be about 20 hp. Most of the parasitic loss of power has already taken place, so when the motor spins up to it's tq / hp match (5252 rpm) and it produces 300 hp, the parasitic loss may only be 30 hp, or 10%. I guess what I'm trying to say, but not doing it very well, the parasitic loss to the rear tires does not increase at the same rate that HP does, since power has already been used to start the spinning momentum. After seeing a few LT4's on the dyno, they produce about 295 - 300 rwhp stock and the factory claims 330 at the crank. Granted, the peak HP is higher in the rpm band than the L98, but the parasitic loss should be similar. My guess if motor produces in the 350 chp range, it would be more like 310 - 315. I believe 280 would be extremely conservative. All of this is just theory of course. Does this make since or am I just out in left field somewhere? One thing is for sure, if the motor produces 350 chp, you will definitely notice a difference over the stock rating!![/quote] The LT4 is a strange animal. Many suspect it was WAAAYYY under rated. That being said, 20% is on the high side, probably closer to 15% many will say 15-18% Point is, 350CHP will not yeild 300 RWHP under the best of circumstances. I think closer to 285. |
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Posted on: 2008/8/19 1:54
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| Aboatguy | Re: HP estimate | ||
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Senior Guru
 
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I believe the better than expected LT4 dyno numbers come from every LT4 having a manual tranny. Most of the LT1s and L98s that came with an automatic.
Automatic cars dyno lower than manuals and higher stall torque converters throw the dyno number off even more. Andrew, the dynojet is a heavy drum with a known mass, and they measure the increase in the acceleration of the drum. They have a formula that predicts the horsepower, so you always have momentum and believe it or not many factors affect the horsepower results even things like the wieght of tire/wheels, rear end gear ratio....... Dyno losses are usually quoted as being 10 to 20%. IMO these numbers are useless, as a comparison to another cars results on a different dyno. Many cars that dyno poorly perform well on the track/street and vice versa. So what counts is what your car dynos before and after the mods (on the same dyno) Now for the original poster, I'd mod the exhaust, rear gears, intake, then heads cam, last. If you have a automatic don't forget a good stall converter. The reason why I suggest gears before cam is; nothing sucks worse than having a highreving high performance SBC that won't come off of the line because you don't have enough gear to get the engine in the power band. (Experience gained through a rooky error I committed back in 1981 and won't repeat) Mike |
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Posted on: 2008/8/19 2:21
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| JonnyAngle | Re: HP estimate | ||
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Senior Guru
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Quote:
I've got LT headers, already with true duals. I thought gears were the last thing you wanted to change. "work from the front of the motor and go back." |
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Posted on: 2008/8/19 2:33
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When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
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| jsup | Re: HP estimate | ||
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Elite Guru
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Quote:
Since your exhaust is done, I'd go cam, intake, cheap set of 1.5RRS like Scorpion. There's your $1500 right there. Do the heads next year along with GOOD 1.6 RRs. IMO gears are something you do AFTER you make power, not before. |
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Posted on: 2008/8/19 2:39
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| anesthes | Re: HP estimate | ||
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Master Guru
 
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Quote:
Not his stock heads. '86 has iron L98 heads. -- Joe |
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Posted on: 2008/8/19 10:32
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| anesthes | Re: HP estimate | ||
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Master Guru
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I'm going to give an alternate opinion because, well I've built a lot of combos which I think is more important than keyboard theory.
I think 180 heads are nice for 305s. Do any of the posters here have any timeslips with the 180 heads on *their own combo* ?? I have not seen any, but I could be wrong. A 195cc head is about the smallest I go with for performance applications. Some of the best combos I've built were with 200cc sportsman heads. As jsup pointed out, the TFS heads are a good deal too. I'm referring to the 195cc 23* heads. They flow 254/185 CFM, have fast burn chambers, etc. For a cam, you really cannot beat the comp 503, or similar grinds. I've tried numerous cams from as small as edelbrock 1002 to comp 306s and I just keep going back to that 503 cam. (224/230). The thing just makes tons of usable power from 2000 - 6000 RPM, which is what you want for a street car - yet still builds enough torque to keep the car rolling in 6th gear on the highway. As far as intakes go, I'd match it with a miniram 1205, a victor EFI with a dog house, converted LT1, or maybe even an HSR. Without any disrespect to folks trying to sell super rams (because we know they are WORTH a ton of money) I think the manifold is an absolute turd and only useful if you live in California and need the EGR/carb approval. Considering I've built my own intakes, done back to back testing with numerous intakes, and have been the moderator of the 'alternative port EFI board' over here: http://www.thirdgen.org/techboard/alternative-port-efi-intakes/ well then I think my credentials are ok.. -- Joe |
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Posted on: 2008/8/19 10:40
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| jsup | Re: HP estimate | ||
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Elite Guru
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Noted, not a SR fan...got it Anyway... you have $1500 to spend NOW what do you do? |
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Posted on: 2008/8/19 13:36
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| FATED | Re: HP estimate | ||
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Guru Newb
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I sorta agree with anesthes.
Except, a milder cam is in order if you want to drive this thing on the street. I don't know what kind of transmission you have but if you have an auto the torque converter will have to be changed. There goes your budget. I also assume you already have the aluminum heads, if not there are some good flowing iron heads out there cheap but you must watch your compression ratio. |
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Posted on: 2008/8/19 14:00
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| JonnyAngle | Re: HP estimate | ||
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Senior Guru
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Even if I go to the 195cc heads, won't the tune be able to make it more streetable? Heads and cam are up in the air still. I would like to give the BBK intake a shot. 3.54's in the rear. What kind of stall do I need, or do I need to know the heads and cam first?
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Posted on: 2008/8/19 14:24
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When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
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| anesthes | Re: HP estimate | ||
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Master Guru
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Quote:
Total or on the intake? If he only has $1500 total he's in trouble. I'd open an ING account and forget about the car. If he has $1500 to spend on an intake, he has a lot of options. A miniram, an HSR, a converted LT1, a victor EFI with a doghouse + an LS1 throttle body to CAI, or a 4bbl with a drop base filter. I've had a couple singleplanes and they all work very well with port injection and a smaller cam. (224/230). I've had a lot of success on street motors with a monoblade throttle body. Throttle response is a lot better than the twin or 4bbl designs. Plus the LS1/Vortec IAC's seem to work a lot better than the older style IACs. -- Joe |
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Posted on: 2008/8/19 14:42
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| jsup | Re: HP estimate | ||
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Elite Guru
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Total.
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Posted on: 2008/8/19 14:42
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| anesthes | Re: HP estimate | ||
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Master Guru
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Just read his other post about the $1500 / year. I'd spend the first $1500 on cam and heads. Either a 219/224, or 224/230 cam. 64cc alum heads might make him run slower, luckily he can have them angle milled for about $200 (so $1300 for heads, $200 for a cam). Might go over budget by $100-150. Some iron heads could flow well and save some money too. Sportsman II heads, with the 224/230 cam, stock TPI is a proven combo for 13.50 @ 103mph. Change out the intake the next year and it's in the 12s at around 107-108mph. Man. I've had a lot of combos and wasted a lot of cash over the years.  -- Joe |
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Posted on: 2008/8/19 14:47
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| JonnyAngle | Re: HP estimate | ||
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Senior Guru
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Yeah, I just want to go $1500 per year on it. I want to stay fuel injected. Getting the plenum ported, and bigger runners and porting the manifold doesn't seem to have as much of an increase for the little extra scratch it would cost to just buy a new intake. Now that I think about it, the intake may be more beneficial to do first. The cam, heads, and TC in a year or 2 and do those 3 at once. Finally, 3.57 in the rear end and keep the D36.
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Posted on: 2008/8/19 16:05
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