new 383 stroker with sad sad dyno results please help

[steve1ph]

hello, glad to be among fellow vette owners. i need help bad for the next upgrade to achive 350+ hp. the specs are: 90 l98 6 speed stroked to a 383. new crank, rods, bearings, pistons (30 over), double roller chain, center force clutch,custom grind bullet racing cam with 503.-510. lift. stock 58cc heads, 3 angle valve job, bronz guides stiffer springs, stock rockers 1.5. stock intake ( i call it the spider). ram air breather, msd 6a iginition, hedman long tube headers and borla cats. there is a aftermarket chip in the computer that was there when i bought the car. stock rear end. stock fuel system, 160 degree stat. about 6k miles on the engine. i drive the car every day great gas milage nice lope and sound. but here is the problem. i had it dyno`ed at speed tek here in dallas tx and i wanted to cry. 6 grand out the pipes. it came in with 265hp and 376trq. i need help bad on intake and or heads or what ever else yall can think of so that i can achive my goal of 350+ hp. thanks a million trillion for your advice. i was so disappointed.

 

[81LT4]

l89

WWW.TPIS.COM, IS WHERE YOU WANT TO GO FOR REAL HELP
WITH TPI MOTORS. i ALSO HAVE A 1991 T/A GTA, FOR ABOUT A
GRAND THEY SAID THEY HAD PARTS AND TRICKS TO GET ME RIGHT A 300+

 

[Mad-Mic]

yeah go with a set of heads an intake and you'll pass your 350 hp mark

now remember 350 at the wheels is close to 400 at the crank.

also get a good set of mufflers. those stock muffs are restrictive!

good luck!

 

[grumpyvette]

swap to afr 190cc heads with the l98 plug angle and port your intake base runners and plenum, that alone should get you very close, add a STEALTH RAM with CUSTOM PLENUM to fit under your hood and youll easilly gain even more hp

http://forums.corvetteforum.com/zerothread?id=569309

 

[vader86]

I would get a custom chip made for the modifications, that SHOULD free up some more power, especially if the one in it is not setup for the cam. Try Ed Wright at Fastchip.com

I would also like to know the duration of the cam, and all its other specs.

Switching to 1.6rr will certainly help also. Maybe 10-15hp.

The TPI setup should be good enough to get you a little over 350hp, with the right cam, and enough portwork on the intake. If you have the STOCK intake, you should get a new base manifold (tpis, edelbrock or lingenfelter) and some large tube runners. Or at the very least port and siamese the hell out of it.

 

[Vettelt193]

the intake at the very least needs to be ported and polished. heads should be done too. The way it is set up now is like trying to breathe through a straw.

 

[WhalePirot]

The chip will make or break any modified engine. It must be custom and probably NOT mail order. Was my situation, anyway.
Now, my car is about the fastest around, thanks to many hours of programming by Gary and Leonhardt Corvette. He's not eager to do another.

Mike

 

[Edmond]

Looks like everything is good except for the heads, exhaust and chip. I would do the heads and exhaust because the chip will have to be calibrated for those mods. Better yet, do em' all at once.

Most performance chips like Hypertech are just generically burned and you won't see much for your money.

Yeah, that chip will make or break the engine. It's like the body wants to do something, but the brain won't let it. Therefore, the body can't do it.

 

[Steve92LT1]

Heads are a MUST. They make or break your engine combo. Stockers are severely choking your motor and will NOT make the power you want. AFR's or Canfields are great, but there are others as well. World Products and Trick flows are about $500 cheaper than the other 2. OR you could spend about $1000 and have your L98 heads "worked". I would really go aftermarket though.

So is the "stock" TPI intake manifold, it chokes a stock 350. It sucks. Either get a superram or miniram OR get some highflow runners and port the lower manifold and upper plenum. It can be modded to flow decent.

A chip isnt going to make or break your combo, only will optimize what you have and get the most out of it. It wont make a world of a difference unless your car is running like crap. I would goto http://www.pcmforless.com and have him do your programming. It's like $125 and it's for "your" combo. I would wait until you upgrade everything else first.

There is power to be made and it has potential. The motor just needs to be opened up. Remember your engine is basically an air pump and the more air you flow through it the more power it will make.

Good Luck!

 

[WhalePirot]

chip isnt going to make or break your combo

Wanna bet?

With only headers, some head/valve work and a mild cam in my car, I was getting replies to my exhaust smoke from various Native Americans, using their traditional means of communication. This was true even after TWO (albeit minimal) custom shots at the chip, by a well reputed ECM guru. Sure, the car ran okay; even slipped by the SMOG guy, but it never ran as it should have run.

Now, my 406 beat all California SMOG requirements and exceeds my expectations, all due to the chip as an integral part of the system. This one MADE my car, but cost over a grand to do properly.

You'll never see the engine's full potential with a mail order chip. Any builder will tell you that two 'identical' engines are not the same. I totally agree that the chip is the final piece of the engine puzzle. The better it fits your engine, the more optimal will be your result. WHEW! I feel better!

Arizona Speed and Marine runners and the Lingenfelter intake worked well with the stock plenum for a pal's 406. The heads probably, as a minimum, need flow work and enlarged valves to breath. Also, ensure your injectors are sized for the power you expect. See: http://www.jimsperformance.com/tech.html

Welcome to the frustration of a less-than-total approach to the engine system. Sorry to hear it.

Mike

 

[Vettelt193]

I will come in here in the neutral zone. For this situation, the chip is not at the top of the list. The engine has obvious choke points with the intake and heads...

a chip will get the full potential out of the engine, BUT, he needs to get the engine in balance first. (what I mean by balance is get rid of the bottle-necks)

Once the intake and heads are done, a chip will get the max power out of the properly balanced package.

 

[8388]

No way, your gonna hit 350 @ the wheels if your running the stock TPI. The engine will run out of rpms long before you can achieve it. Yes you either need to massage the factory heads ( by a professional ) or just go AFR's. but the stock TPI has got to go. Are you running the ZZ3 cam ? what's the duration @.50 ? If you want to maximize hp get the mini ram intake with the proper camshaft.

 

[*89x2*]

I will come in here in the neutral zone. For this situation, the chip is not at the top of the list. The engine has obvious choke points with the intake and heads...

a chip will get the full potential out of the engine, BUT, he needs to get the engine in balance first. (what I mean by balance is get rid of the bottle-necks)

Once the intake and heads are done, a chip will get the max power out of the properly balanced package.

I agree with that Heads / mached first... A chip by itself won't do wonders but will get you there once bottlenecks are gone

 

[grumpyvette]

http://www.eecis.udel.edu/~davis/z28/winter01/dyno/dyno021105/webpage021105.html

by far the biggest gain you can make to a TPI is the REMOVAL of the HIGHLY RESTRICTIVE STOCK TPI INTAKE that flows about 190cfm-200cfm and REPLACING IT WITH A CUSTOM STEALTH RAM.that flows 275cfm-300cfm with minor port work.
all the parts in an engine combo must match the intended RPM RANGE and AIRFLOW, in order to make the required hp level. lets take my 1985 corvette for an example, you can use your own combo, but as a general guide follow how a correctly matched combo is figgured out
the intake choices are. STOCK OR MODIFIED TPI,which falls on its nose at 4500-4700rpm air flow wise ,or the stealth ram which operates best in the 4000rpm-6400rpm range, and flows about 275cfm out of the box, both can gain about 25cfm with porting.
a cam that works correctly in that 4000rpm -6400rpm range will have at least 220-230 degrees duration (230-240 would match well,(being driven on the street I picked a cam with 230 duration)to get the full potential
(IM useing a CRANE 119661)(installed 6 degrees retarded) (with that cam I need a STATIC COMPRESSION RATIO OF 11:1 and a DYNAMIC COMPRESSION RATIO UNDER 8:1 WHICH I HAVE)
http://www.prestage.com/Car+Math/Ge...io/default.aspx

http://www.btinternet.com/~mezporti...ust_length.html

http://home.isoa.net/~mharrisj/pistspd.html

http://www.rbracing-rsr.com/runnertorquecalc.html


http://www.prestage.com/Car+Math/Ge...PH/default.aspx

your cylinder heads should flow a minimum of 245cfm-260cfm @.500 lift to reach the full potential of the intake but ewven stock heads show a big gain from the far less restricted custom stealth ram that you choose that is able to flow slightly higher flow numbers to make the required hp/tq curve and to keep the engine in the proper rpm range youll be trying to stay in that 4000rpm-6400rpm max tq in the dyno curve.
http://www.prestage.com/Car+Math/Ca...as/default.aspx
http://users.erols.com/srweiss/calcafhp.htm
http://users.erols.com/srweiss/calchpaf.htm

the bottom line is that a correctly built combo requires carefully matched parts designed to work at the SAME HP and RPM levels,MISS-MATCHED COMBOS DON,T TEND TO REACH THIER POTENTIAL,and BADLY MISS-MATCHED PARTS WILL TEND TO WORK AGAINST EACH OTHER AND COST YOU HP!
heres what I built
custom 383 full roller ,11:1 cpr,engine CRANE #119661 0.21 thick copper head gasket/.o20 deck/piston height ,hydrolic roller (installed retarded 6 degrees) cam,ported trickflow 200cc heads,(about 210cc now)custom stealth ram, 32lb (testing 36lbs now) injectors,custom chip,custom built plenum,58mm throttle body,6" rods, slp forged pistons,total seal gapless rings 9.5 qt baffled custom oil pan,milodon windage screen,jackson gear drive,1 3/4 x36" with custom merge collector headers, full 3" exhaust, 1.6 erson roller rockers, 200hp nitrous plate,all forged rotateing internally ballanced assembly,fluidamper ballancer polished combustion chambers,ballanced engine , splayed 4 bolt block, LS7 oil pump,all internals pollished, and no I won,t tell you my E.T. or HP other than to say , C-5 ZO6s aren,t a challange and they run mid 12s

if anyone cares to work that out on DD-2000, let me know what you get, BTW the stealth ram is a EFI tunnel ram intake with an 1050cfm throttle body)
heres more info
http://www.geocities.com/jgkov/L98Mods.html

http://www.ws6.com/mycar.htm


http://www.corvettefever.com/techar...9156/index.html


http://www.eecis.udel.edu/~davis/z2...page021105.html

heres a picture of a custom stealth ram installed in a C-4 corvette

if you want more info E-mail me. but a combo of the new custom stealth ram. better heads and a matching cam makes A HUGE DIFFERANCE IN PERFORMANCE

 

[bossvette]

I agree the heads and stock TPI are the bottleneck I have a 383 TPI with Brodix street heads slp runners and quite a few hours of die grinder work. I did not know custom chips were so expensive you may want to look at a programable system like the Holley commander 950 it is simple to use and their tech support is excellent.
when I built mine Holley did not offer the TPI type system only the electronics or I would have gone that route (complete system)and saved a bunch of money. Accel also has a system, but at the time I was building mine they were still using a dos software.
one of the biggest benifits of these systems is if you make a change, just hook up the laptop and go to it.

 

[grumpyvette]

yeah the laptop programable EFI software is the best way to go, because you can make those small changes necessary for best performance with just a few key strokes on your laptop rather than relieing on a chip and the ultra slow chevy processor speeds PLUS a HOLLEY STEALTH RAM, WITH CUSTOM PLENUM,AND HOLLEY SOFTWARE can be set up to run far better on a larger displacement combo than the stock chip controlled setup designed for a low compression very mild cam chevy software, and a cam with over 220 duration won,t drive it crazy like the stock chevy ECU with out a custom chip. as Im sure youve noticed the stock TPI falls off a cliff flow wise after about 4500rpm, so any changes you make to the engine useing a TPI had better be matched to the TPIs effective flow range of 1000rpm-4500rpm, includeing the cam choice, ignition timing, and injector size.
the combo of a custom STEALTH RAM AND SOFTWARE, plus upgraded heads and cam is easilly worth 90-120hp plus over a stock TPI, now that might not sound like much but a stock TPI has 230-245hp, adding those changes can get you running up with the newer corvettes

 

[69MyWay]

I am sure you have a few more ponies in there right now you just can't get to them because of a few minor adjustments.

You really need a scanner hooked up. What you want to do is watch the spark knock/timing retard during your dyno run. If you are not getting any...advance the timing. Advance the timing to where you are just getting 2 degrees or so of retard around WOT. That alone can make 35 hp at the rear wheels if your timing is way off.

Second, with an adjustable fuel pressure regulator, you can then turn in a few more pounds of pressure, and run again. That will add a extra bit of fuel that will combat detonation. You have to adjust the timing and fuel pressure for maximum WOT results.

I would also suggest that with a stock intake, you should not run to 6,000 RPM, as you will be making more power around 5200 due to the flow characteristics of that intake.

Try the timing first, and see if that does not pull you around.

 

[grumpyvette]

your potential gains if any will depend on the total intake system and exhaust air flow,how badly the stock 48mm throttle body was restricting the engines airflow before the swap, of any parts , how well the cam ,intake,exhaust, and cylinder heads match and how well the cumputer controls all the sensor imput/controls, it the TPI INTAKE and CYLINDER HEADS NOT the throttle body are whats the big resrtiction take the time to read the links

http://www.eecis.udel.edu/~davis/z28/winter01/dyno/dyno021105/webpage021105.html

have you ever noticed that in all the years everyones been swapping to 52mm and 58mm and mono blade 1300 cfm throttle bodies , they have said things like
I did not gain a great deal of hp
I lost some throttle responce
It sounds differant but I don,t seem to go faster
I only gained a tenth of a second plus a couple thousands in the 1/4 mile

Ive yet to find anyone that lost hp,once the engine was properly set up and adjusted with the larger throttle bodies
a throttle body is not like the venturies on a carb that control the fuel/air mix, the computer and sensors and injectors do that on an EFI system, the throttle body is only a air volume control valve, your engine can only use (X) amount of air at any given point, as long as the throttle body is allowing that much OR MORE to pass UNRESTRICTED, its going to work reasonably well. the individual ports combined on even a 454 size sbc spinning 6500rpm (WAY OVER ADVISEABLE PISTON SPEED) only can use about 850-950cfm (do the math) that can be fed from dual 56mm throttle bores, since a 58mm is the closest size thats what most guys with large engines use,a 383 like mine with a custom stealth ram only needs about 775-825cfm. a 52mm is just a little to small and a 58mm is overly large BUT, TOO LARGE, WON,T HURT PERFORMANCE NEARLY AS BAD AS TOO SMALL or RESTRICTIVE MIGHT! ONLY TOO RESTRICTIVE/SMALL hurts!
yes you might lose a small amount of throttle responce, but an overly large throttle body won,t hurt high rpm hp if mounted on an engine with an intake with the correct port runner size/length, compression and cam timing. don,t forget that a great deal of how effective an intake system is is controlled by the rpm range where the exhaust system on that same engine scavages the cylinders efficiently. if you don,t have full lenght tuned headers and a free flow exhaust , adding a larger throttle body is likely a waste of effort. if you cant get rid of whats in the cylinder now you can,t refill it effectively anyway. keep in mind an engine is A SYSTEM, ALL PARTS MUST BE DESIGNED TO WORK EFFECTIVELY AT THE SAME RPM,AND DISPLACEMENT.
HP is MORE THE RESULT OF HOW EFFICIENTLY you can pack fuel/air ,into a cylinder, burn it efficiently, and get rid of it , useing its energy to reload the next charge than almost any other factors, useing a larger throttle body can help!
I just swapped from my 58mm back to the stock 48mm as a quick test on my 383 corvette, guess what! the stock throttle body made the vette noticably SLOWER!!

a 350 has a 3.48" stroke, a 383 has a 3.75" stroke , the 396 , has a 3.875" stroke but tends to cost more than the slight additional power is worth , you might as well build a 401 if you are going to that trouble (check the AFR article) because of the additional part costs and clearances needed in machineing the block. you won,t get 450-500 rwhp without nitrous or a supercharger, that would require about 535hp-600hp at the flywheel. yes, I know everyone has a BUDDY that HAS a FRIEND, who KNOWS a GUY that has 500rwhp,from a 383, (unless your willing to spend over about $7000 MINIMUM , don,t reasonably expect that hp level without nitrous IN AN ENGINE THAT WILL LIVE VERY LONG,

DO YOURSELF A BIG FAVOR
buy these FIVE books, it will be the best money you ever spent, read them, and you will be miles ahead of the average guy.
HOW TO BUILD THE SMALL BLOCK CHEVEROLET by LARRY ATHERTON&LARRY SCHREIB
.
HOW TO BUILD MAX PERFORMANCE CHEVY SMALL BLOCKS ON A BUDGET by DAVID VIZARD
.
JOHN LINGENFELTER on modifying small-block chevy engines

how to build & modify CHEVROLET small-block V-8 CAMSHAFTS & VALVTRAINS BY DAVID VIZARD

SMOKEY YUNICK,S POWER SECRETS

THE DISPLACEMENT,CYLINDERHEAD FLOW and cam timing and compression ratio are the major factors in how well the basic combo will work, of these watch the compression ratio matches the cam timing, the larger the displacement the better and cylinderheads are one of the most important parts in the whole combo!
heres some info you can use

http://phil.tobin.net/Hoover/index.html (lt1)

http://www.gmmodernmuscle.com/383/383build.html

http://www.sa-motorsports.com/blockdiy/blkdiy.htm

http://www.grapeaperacing.com/Grape...isplacement.cfm

http://www.speedomotive.com/building tips.htm

http://victorylibrary.com/mopar/cam-tech-c.htm

http://www.bracketmasters.com/small...oker_383_cu.htm

http://www.geocities.com/jgkov/L98Mods.html

http://www.ws6.com/mycar.htm

http://www.eecis.udel.edu/~davis/z28/winter01/dyno/dyno021105/webpage021105.html


http://www.airflowresearch.com (articles)(401-Inch Chevy Stroker)

youll need a custom STEALTH RAM, port work, a roller cam like the CRANE #119841

http://dab7.cranecams.com/SpecCard/...B1=Display+Card
a laptop controllable ECU like the HOLLEY 950 ECU, and 36 lb injectors

build the basic engine in the AFR article, use the crane cam above (it matches the flow characteristic of the stealth ram more closely and will work better with EFI)
use the AFR 190cc heads (fits the stealth ram ports better and builds tq faster yet the flow figures are almost identical to the 195cc heads)
boost the compression to 11:1 for increased tq,(the cams duration will bleed off enought low rpm compression to keep you out of detonation)
add a 175 hp nitrouse kit behind the throttle body and if you can drive, you add slicks and suspendsion work and you can tune an EFI motor , high 10 second 1/4 mile e.t.s will be available

buy the books, read the info BEFORE SPENDING MONEY, and keep in mind that those engines David Visard builds are ported by an expert and your highly unlikely to get those results, use PORTED 190cc AFR heads, even D.Visard would tell you they flow better

heres a custom stealth ram intake on a 427 sbc

HERES ANOTHER CORVETTE WITH THE CUSTOM STEALTH RAM INSTALLED

http://www.geocities.com/jgkov/L98Mods.html

http://www.ws6.com/mycar.htm

a CUSTOM PLENUM HOLLEY STEALTH RAM,CAM and CYLINDER HEADS SWAP will make a HUGE differance in the corvettes hp

a CUSTOM PLENUM HOLLEY STEALTH RAM(necessary to fit under the C-4 hood) ,CAM and CYLINDER HEADS SWAP will make a HUGE differance in the corvettes hp , FAR EXCEEDING ANYTHING YOU CAN DO TO A STOCK TPI STYLE INTAKE, GAINS IN FLOW OF 20-30cfm by porting a STOCK TPI are hard to get, a CUSTOM STEALTH RAM (necessary to fit under the C-4 hood) flows 75cfm better out of the box -100cfm PLUS better with minor port work! a complete STEALTH RAM with custom plenum out flows them all out of the box EMAIL ME FOR DETAILS
read this

http://victorylibrary.com/mopar/cam-tech.htm

http://www.mercurycapri.com/technical/engine/cam/lca.html

http://victorylibrary.com/mopar/rod-tech.htm

http://www.zhome.com/ZCMnL/PICS/detonation/detonation.html

http://www.chevytalk.org/threads/showflat.php?Cat=&Board=UBB64&Number=397334&Forum=UBB64&Words=LSA&Match=Entire%20Phrase&Searchpage=3&Limit=25&Old=allposts&Main=397176&Search=true# Post397334

if cams are a mystery please take the time to read these, it will get you a good start

http://www.newcovenant.com/speedcrafter/tech/camshaft/1.htm
(read LESSONs 1-8)

http://www.mercurycapri.com/technical/engine/cam/lca.html

http://www.wighat.com/fcr3/confusion.htm

http://www.cranecams.com/instructions/valvetrain/camfail.htm

http://www.mercurycapri.com/technical/engine/cam/index.html

http://www.idavette.net/hib/camcon.htm

http://www.cranecams.com/master/adjustvt.htm

http://www.centuryperformance.com/valveadjustment.htm

http://www.totalengineairflow.com/tech/valvelashing.htm

http://www.chevytalk.com/tech/engine/Cam_Selection.html

http://www.chevytalk.com/tech/101/Cam_Theory.html

http://www.babcox.com/editorial/ar/ar119736.htm

http://www.mercurycapri.com/technical/engine/cam/vtg.html

http://www.n2performance.com/lecture1.shtml

http://www.symuli.com/vw/camp1.html

http://www.symuli.com/vw/camp2.html

http://home.wxs.nl/~meine119/tech/camqa.html

http://www.chevytalk.org/threads/showflat.php?Cat=&Board=UBB64&Number=200511&Forum=UBB64&Words=your%20kidding&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=allposts&Main=200510&S earch=true#Post200511

http://www.crower.com/misc/valve_timing_chart.html

http://www.speedomotive.com/Building Tips.htm

http://www.kb-silvolite.com/page05.htm

http://chevyhiperformance.com/techarticles/94138/

http://www.aera.org/Members/EngineTech/engine.htm

http://www.zhome.com/ZCMnL/PICS/detonation/detonation.html

 

[l98vette1986]

just my .02

how much duration @ .050 does your cam have? In order to make higher HP, you need to pull those heads off, throw them in the dirt, then look for a good aftermarket head w/ 180-190cc intake runners. If i were in your shoes, i would get a set of Sportsman 2's. They are damn good heads. That will help avoid the extra cost of aluminumn heads. Stay away from long runner intakes, the 383 will run out of steam much faster than a 350 will as far as RPMs. RPMs are what you want to make higher HP. If possible, try and get a Mini-ram, they work excellent for HP, and dont listen to the BS that people say as far as a miniram not having any torque on the low end.. That i snot tru, they put out more torque off idle to 2,700 RPMs than even the stock TPI. i have a miniram on my vette, and it seems that under normal driving conditions i am shifting at 3,000. This will end up being your best bet, and give you the best results. Right now i am building a 377 stroker for my car, i am gonna use ported edelbrock heads, and my miniram intake on it. You can bet that its is going to be fast...

 

[grumpyvette]

I had a mini ram installed on that engine for over three months, at least on that particular combo it WAS NOT the hot ticket, in fact it was quite a bit less effective at pulling a wide tq curve. now no one ever said its not possiable to pull good peak hp numbers with a miniram but untill youve tried all five comon intake systems
btw the ported TRICKFLOW HEADS OUT FLOW THE HEADS YOU SUGGESTED, IVE USED THOSE HEADS ON OTHER ENGINES IN THE PAST BOTH PORTED AND UNPORTED
TPI

super ram

miniram

custom stealth ram

MODIFIED SINGLE PLANE

IVE RUN ALL FIVE