EDIT: One video is up... not on my camera but my buddy taped it and put it online. i didnt know he was doing it lol. mine will have abit more sound quality but its not bad just not as loud as it is in person http://www.youtube.com/watch?v=Xv-DllPZoWo Since the last dyno run of 246whp i've added 1.6 rockers, underdrive pullies and played with the tune. To my surprise my tune wasnt as good as i thought. Car is a stock L98 longblock...stock heads/stock cam stock internals Car has Stealth Ram, 1.6rockers, underdrive pullies, afpr, 24lb injectors, and full exhaust--> Hooker shorty headers and custom 3inch catback, gutted cat. 2800 stall 3.42 gear. Car has gone a best of 12.95 at 103.83 in great air last weekend I locked the converter on these runs early so i got a good read out from about 3000rpms to 5500 according to the tach, but the dyno read out showed mph and as calculated from that, dyno runs stopped at 5200rpms or so...BUT hp is suppose to cross torque at 5250rpms or something like that, and on my chart it looks to be about 5000rpms. so i think the rpms are off! So maybe the dyno didnt pick up a good read on the tach pickup? could that change my power numbers? who knows Either way the numbers are in: 254whp at what is calculated to be 4800-4900rpms but i really think its 5000-5100 and 315wtq at 3100-3300rpms. Torque curve is pretty flat from 3000-4000rpms then it starts fading off. if the dyno speed is wrong, then it looks as if my peak hp occured at 5150 or so. no big deal tho, as hp is flat from what looks to be 4500rpms to 5200 or so lol. AFR was 13.5 to 1 till about 4300rpms where it rose to 14.5 to 1. so tis very lean and needs work. i figure 5-8 hp more from abit richer mixture. weather was abit cooler as well so i dont think i really gained all that much from underdrive pullies and 1.6 rockers. I think the 1.6 rockers made it run much leaner and i didnt add fuel to compensate.

Thanks for the info!!!!!!
Hard numbers are great, and I think that I can speak for the masses that we all apreciate them.

I plan on getting some dyno numbers in the spring before my build up. Then post the after build numbers. This way other people will know what to expect from different combo's. Unfortuately estimations are just that....... estimations

Thanks once again!!!

Get the AFR around 13.0 across the board and you will see a bigger gain. If you notice the biggest gain is after peak HP compared to the stock TPI. How much different is the HP at 5100rpm with the HSR compared to stock TPI?

oh man i bet the difference is huge! i never did get a good dyno run with TPI. when i did i had my EST wire disconnected when i set timing the night before and forgot to hook it up at the dyno!! only put down 200whp at 4100rpms lol but thats with a LOT of timing pulled out. i estimated it to be around 230-235whp with stock TPI at around 4300-4400 rpms but thats only estimations. HSR pulls HARD after 4400rpms and carries to about 5200rpms with stock cam it seems.

i really want to get the airfuel down to 13.0. hope to see 10hp from that but dont wanna over estimate it. i just got back from playing with my tune..i added more fuel up top end but i dont have a wideband so i cant tell whats goin on.

nice results and the sound vid was great

You will be doing good to get 10rwhp with the air fuel ratio change. I have never got that much and with more power to start with. However VincentZ28 might have but he has 100 more rwhp at 5000rpm.

Looks like with a good set of heads, cam, tune and chasis set up you might be knocking on the door for high elevens with good air. Lower 12's for sure.

Will do the same next year on my friends camaro, everything stock except the exhaust and a HSR..... and a custom prom made by me

Please keep us posted

/N.

how much power can you get from adding fuel to make it around 13.0 from 14.5? if i picked up 5 i'd be happy as it would put me so close to 260whp from bolt ons.

this wasnt a load bearing dyno so they say when your on the street, the car's real afr will be a few points lower than what the dyno says and that i may be at around 14.0 to 1 on the street. he said you want to be 2-3 tenths high on the dyno. my airfuel from 3000-4200rpms is fine, i just need to make the rest match it. i really want a wideband now

one video is up!
http://www.youtube.com/watch?v=Xv-DllPZoWo

What's your timing in the engine? Once you get the A/F in check, you might want to try messing with it a little bit more.

You might want to either raise the PE about 3 whole points or the VE about 2...that would put you close from what I have seen leaning out my tune.

Tune it up and you'll be close to the 270 marker I thought you would be at.

Also, was this wideband at the rear of the exhaust and do you have a cat?

I`ve been thinking about going with the hsr.If you`ve dipped into the 12`s with a bolt on L98 I`m sold.I just cant decide what to do first,gears and stall or hsr.Great numbers for a n/a L98 not on the bottle

What tires did you have on there on the dyno? That or a chart with RPM instead of MPH would be nice

i had 25.7 inch street tires..standard 245/50/16's but they are abit worn down. I'm asking the dyno guy to send me a new chart with RPM on the bottom, as if you convert those mph's to rpms it doesnt come out right. hp/tq dont cross at 5000rpms lol

Right now i'm running 35 degrees total. i got 8 degrees base timing with the dizzy and corrected in the chip. i added 2 degrees to whole table then an extra degree in the WOT tables from 3600-4800+rpms, basically bringing near full timing in sooner. i have 34 degrees from 3600 to 4800 then 35 degrees at 4800 to redline

I have MAF so i dont think i have VE tables. once i richen it up, should i add more timing? 36 degrees too much for a mild motor? i've always heard most motors like 34 degrees. just with my timing mods, i've gained near 12lb feet of torque at peak and even more so across the curve.

the air fuel was a wideband meter that was inserted into the tail pipe. I dont have a cat anymore, its completely gutted and i dont have AIR system either so no fresh air is getting in there

Shady, i think gears and stall are a better investment and you'll see more gains right now with those mods. everyone says HSR kills soo much of that TPI torque and it may definately do that, but with a good stall speed, you dont have to worry about torque loss. you may notice loss with stock converter. But i still have 315lbft at the wheels where i need it, just ahead of my stall speed. i want to get a restall to 3200 now instead of 2800

Thats an interesting dyno... I would have thought the RPM's would have been higher at the peak but obviously its not. Same flattening HP 'curve' I've seen on stock TPI's but you have a few hundred more RPM on the powerband.

yeah its the heads/cam profile that makes that flat powercurve i'd say. low duration and very wide LSA.
I have another graph that shows a zoomed in section of where my tq/hp crosses and shows rpm instead of mph. that graph looks correct and it crosses at 5250 rpms or so. by that graph peak looks to be around 5000-5100 but holds to 5200 as well. basically a extended TPI powerband. hopefully i'll get the good full graph of power vs RPM and not MPH

noobie question whats an hsr ?

that car is sick ........ u have a cardomain?

HSR = Holley stealth ram

I dont have a car domain but always planned on making one. maybe i'll make one tonight but i do have some webshot pics and VBgarage here as linked in my sig

How much timing depends on gas octane, compression, cam design, etc. If you're running stock L98 iron heads and cam watch your knock counts. Compression isn't that high, but I'd say 36 might be a bit high. I like mine to come in a littler earlier than you have it, max timing by 3200, but I also like it to taper off a degree or 2 at the top of the table. You added 2 degrees across the board and 1 to the PE? What bin did you start with? I know that my stock bin had a really fubar'd timing table, took a lot more work than that to get it straight. Mine ramps up from VERY fast from 2200 to hit full timing at 3200, holds that then drops back 2 degrees at 4800. I would've liked to hold it longer before dropping back, but gotta work in the confines of the software .
Definitly hit it with some more fuel up their in the rpm band, probably in the PE vs RPM table. I'd bet you'd be able to extend the useable RPM as well if you got that right. Had a similar problem in a 'vette once, car basically ran into a wall at a bit over 5k at 14.2 to 1. Fattened it up to 12.9 and got another 500 useable RPM. Hard to say how much you'll get since you're using stock heads and cam, but I think you're goal is very doable.

EDIT: oh and by "mine", I'm not talking about the 409, I'm talking about the tune I used on my old IROC. Don't want to confuse the issue. The 409's tune is way to aggresive for the stock iron heads.

I'm using my stock AUJL bin to start. the ARAP tables look way to aggressive at part throttle for my tastes.

I added the 2 degrees to the whole timing table to simulate advancing the distributor 2 degrees at base timing. before i got the tuning stuff, i just advanced the dizzy 2 degrees to 8 at base timing instead of 6 and it felt good. i tried 10 but went back to 8. Once the tuning stuff came in i changed my base timin in the chip to 8 to match the dizzy and added the 2 degrees back into the table.

My WOT timing at full LV8 is about 29 degrees timing from 2000-2800 rpms, then 32 degrees at 3200rpms then 34 degrees from 3600-4800, then 35 degrees at 4800 + rpms

you suggesting I increase the timing in the 2000-2800 range, full 34-36 by 3200 and backing off to 32-34 by 4800?


I made another quick tune with more fuel by increasing the MAF table values. I took the car to 4000rpms WOT thirdgear and saw the MAF reading and increased those numbers to max which was around 205-210 grams/sec. Should i go back to what it was and just add fuel via PE vs RPM?

EDIT: Is there anyway to look into the 6E mask and extend the PE spark advance table to 5500-6000 rpms? it stops at a measly 4800 lol

Not backing off to 32-34 by 4800, right at 4800, run full up to then. I actually like to do it around 5200, but the stock maf table only runs up to 4800. Was just something I read somewhere once about tuning timing for higher RPM's vs the effects of lower cylinder filling and higher piston speed that seemed to work well for me.
And yes I like to have full timing in by 3k-3.2k. I usually bring it up very slow (only a couple degrees) to around 2k -2.4k then ramp it up fast to full by the 3-3.2 range. But that's just what I had good results with. You may have to scale it back some if you don't want to run premium fuel. Here's what my WOT curve looked like all added together.
4800 34.10
4400 35.16
4000 35.16
3600 35.16
3200 35.16
2800 33.40
2400 28.83
2200 27.42
2000 23.91
1800 22.50
1600 21.09
1400 20.04
1200 18.98
800 17.93
600 16.88
400 16.17
Keep an eye on your knock counts though, I'd hit knock with cheap gas everytime and sometimes just if I bought premium at a different brand station.
With the stock bottom end MAF vs PE for fueling adjustment is probably just whatever works for you. On my 400 the maf won't give me enough fueling without using PE to richen it up at WOT.
And unless you can write your own code your stuck at the 4800 rpm table.

Oh and on a side note, where you at in Pittsburgh? I grew up in Harmarville, and my mom still lives right on the border of Fox Chapel

I wouldnt mess with the upper MAF tables much. Increase your fuel through the PE vs RPM table.

I'm doing the same thing with the timing as above, all in early and a couple degrees off at the top. I added a whole bunch of fuel at the upper end. Without having a wideband on there you're kinda guessing, so take small steps.

i will be gettin a wideband over the winter... my car goes into storage at the end of this month so haha

I'll go back to the previous MAF tables and just tune the PE vs RPM.

And i'll try a similar timing event. I run 93 Sunoco fuel and i have 94 available there as well i believe so i should be fine. even tho gas is expensive these days the car gets less than 4K miles a year so its fine


I live in Delmont PA which is near greensburg if thats more well known. its about 35min outside the city. I went to school down in Oakland so i kinda know that area fairly well.

Cool, I know right where that's at. Still have a weakness for Rolling Rock and the Johnstown Chiefs

someone will one day have to explain to me how those power levels are possible with that tiny of a cam. I'd believe mildly ported the heads could support that, but not on a stock cam

some guy have better heads then others....LOL

Stock IROCZ cam aint' that bad - at least compared to a lot of them, it specs out close to a mild flat tappet performance cam - he's also got 1.6 roller rockers, and a lot of other bolt on stuff. Back in the day TPIS was getting good numbers with their bolt on long tube stuff. Not to mention that the stock setup leaves a lot on the table just in terms of tune - before you even bolt any new parts on.

agreed! LT1 cars make good numbers and their cams have less duration than the IROCZ cam but the lift numbers with 1.5 rockers for the LT1 are similar to the L98 with 1.6's. plus their heads flow abit better than ours so i can see the bigger hp gains there.

but the biggest thing is i think the tune. good numbers are to be had with just messing with the timing curve and fuel if the car is overly rich stock, which my TPI car was. the HSR helped lean that out just a tad. then i took it from there, and just abit too far lol Still got work to do. I really want to add long tube headers over winter and try to get a cam in it too. If the cam dont fall into place, then i'm taking this car farther into the 12's with what i have

nice numbers.

Quick question, is that with the stock throttle body? Or holley's 58mm.

stock L98 48mm TB

nice numbers and sounds good man!

well i updated my timing table to follow similar suggestions posted above and i added a bit more fuel thru the PE vs RPM. not sure how much that will help without a wideband but i did notice before that i was getting 3-4 degrees of knock retard when i first went WOT in the 4000rpm range then it tapered off abit but still had 1-2 degrees. so maybe that was because of my timing and my lean condition? so with the added fuel i shouldnt see that knock retard?

Soon as the weather clears, i'll take the car out again to see how the new changes act and to see if i get any knock retard

tagged for future results. very informative thread

this is a good read with some good results, I'm tuning in.

well to update i only have a week or so left before i have to store the car for winter. over winter i think i may add a cam and exit the bolt on stock L98 game. I may never know what else the car has in it but i can assure you there is more.

Since i've added more fuel and abit less timing, i've still getting knock retard. Upwards of 4.6 degrees on the initial wide open throttle hit. It does taper off tho as rpms go up to peak before shift. I think it may be false from the exhaust noise/vibrations etc but i dont know. i shouldnt be getting anything from that timing curve i thought.

i've pulled out alot of timing in the low wot rpm range and i think i'm now running 33 degrees at WOT even tho datalog shows 34. knock retard never changed and i was getting some knocking on datalogs. STil running fresh 93 octane. car doesnt feel as fast with the less timing. So i dont know what else to do. I may take it to the dyno ONE more time next week if i can just to see what this thing is REALLY capable of. maybe disable the knock sensor on one run. IDK, i dont wanna spend dyno tuning for stock motor when i plan to run a cam but i am so curious

knock retard was 3-4 mostly and my timing showed 35 dgree til 4800 when i backed it off to 34. so does that mean its really only at 31 degrees or so?

Is your attack rate and decay rate compensated already....if not...you might want to try it.

no i never messed with any of that. i'll look at it. any advice on what to mess change? should i reduce the attack rate? its set at .36 degree per ms from 3200-4800+

I have my attack rate at .16 across the board. And the Recovery rate from 150 gradually up to 200.

well i adjusted my attack rate to .18 in the 3200-4800+ range and recovery rate to 85-90 % instead of 60.

no real change as far as i could see but my laptop and cable werent connecting well today and it hasnt been. on the initial WOT hit and downshift, i was 4.6 knock retard like i've always saw but then after that i stopped connecting and froze up so i couldnt read any other values. i drove for 30 min trying to get it to connect.

i put my previous timing values back in and made max knock retard in PE mode to 3-4 degrees only. I also added another degree to the low end part throttle stuff.

Going from 60 to 85-90 ain't no real difference. Basically its how fast you can recover from knock.

mine is based on percentage recovery. i'm not sure what yours is when you say 150 to 200.

Only getting about 1.8 degrees of retard now. Car feels pretty strong. Last night in the cold air it ran very strong. Felt good. I'm so curious as to my air fuel ratio now and what numbers this thing will put down

Mine is also based on % recovery rate. If you read about the knock rate in the DYI sticky thread, the higher the number, the faster you recovery from knock.

but how can you have higher than 100%? or are you telling me you can make it 150-200 percent and the computer will take it out nearly 2 times as fast? i've only seen other ppl run 90 percent or so

From Grumpy:
The 200% recovery rate doesn't disable the knock sensor (trust me, it's still working fine and pulling out timing in 3rd gear due to a driveline vibration). It adds back the amount of timing pulled out at a rate of 200% per second. So, if you have 4 degrees pulled out, it'll add it back in 1/2 second. At 100%/second, it'll give you back those 4 degrees in 1 second. Since I'm running the stock timing table still and only run 92-93 octane gas, I'm getting no knock throughout 1st and 2nd gears (except a brief but small spike after the 1/2 shift).

400% is max.

cool i'll look into that

I am just curious about your valve springs, are they still the factory ones? The factory one's were weak to start with and with 1.6 rockers that may explain your power drop off at higher rpms. I know the cams don't support much rpm, but I have found these (factory) valve springs to be really weak even on very low mile cars.

I am not real suprised at the power you are making with that intake and bolt ons. I know in good weather (55 - 60 degree's) and with my nitto DR's my 91 Z with no bolt ons has been a 13.86 @ 98 mph with a 1.84 60'. The only thing not stock on this car is the converter (2200), the cats are gutted, and a little more timing. A new motor is on the stand, just haven't figured out which heads or intake yet.

stock springs as far as i know. I will be rebuilding the heads over winter and mildly porting them/port matching them for the cam swap i plan.