Mike Crews

Hey Guys,

Did my first dyno (Dynojet) runs today on my new motor - basicaly an AS&M LTR 383 TPI with Vortec heads, LPE 74211 cam, and SDPC intake (see my sig for the particulars). Sorry, no scanner, so a summary of the dyno numbers will have to do - and some puzzling numbers they are (at least to me).

Peak HP - 283.5 @ 5300 rpm
Peak TQ - 406.7 @ 3500 rpm
The two curves cross at 5300 with tq and hp both at 283.

The tq curve looks exactly as I had pictured - no problems there with 406 ft/lbs of rear wheel tq :-). However, the hp curve is VERY FLAT from 3500 all the way to 6000 rpm. At 3500 hp is 265, it peaks at 283 @ 5200, and is still at 260 @ 6000 when the dyno run stops. The hp curve is basically a flat line from 3500 to 6000 rpm, not necessarily a "bad thing", just not what I expected. It looks like a curve that someone cut the top off of - there really is no hp peak. The guy running the dyno said that he thought that the 383 was just "gobbling up" more air that the LTR setup could provide, and that I was airflow limited. Last week I ordered a new set of AS&M semi-siamesed runners to see if I can bridge the gap between the LTR setup and a Superram type of setup. I'll let you know what the dyno says about that. The car still runs 12.5s @ 107 at the track, so it's running good.

Anyway, my questions are about the flat hp curve. Has anybody experienced anything like this before??? If so, what caused it?? What kind of rear wheel hp are some of the other LTR
TPIs running??? Any other ideas/suggestions???

Thanks,

Mike

Mark 89Formula

284 RWHP with an LTR setup is definitely comparable to what other folks have posted for a healthy LTR setup. The highest I can recall seeing posted was in the range of 315 RWHP by Kevin91Z with the LT4 HOT cam and ported Corvette heads. The flat HP curve is very characteristic of a healthy engine fed by an LTR setup. Check out some of the Dynojet graphs on Mike's website for confirmation.

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

Mike Crews

Thanks Mark. That puts my mind at ease a little bit. You're exactly right, most of his hp curves are pretty flat as well.

Mike.

GregWestphal

iTrader: (1)

My 355's dyno curve ended up the same way, flat-lined from 4100 to 6000 rpm. With the stock intake runners and TB, Edelbrock base, TF 23* heads, LT4 HOT cam, and over 11:1 compression, I made 257 rwhp at 5650 rpm and 347 lb-ft of torque at 3600 rpm, with more than 250 rwhp from 4100 to 6100 rpm. You can see a graph of the dyno run on my webpage at:

http://www.erols.com/gcwestph/IROC.html

Now with the SLP runners and a 58mm TB, I'm peaking at around 5800 rpm (based on MAF readings), although I haven't been to the dyno to see how much power it's actually making.

dnovotny

I would agree that your dyno numbers look ok if you had a 350. But you have a 383, you seem to be about 10-15% lower in hp/tq vs. what I'd expect. The Vortechs flow well enough that one should be close to 1hp/ci.

I've seen plenty of setups using aftermarket base/runners with AFR heads making around 1hp/ci.

Later, Dave '91 GTA, '01 WS6 T/A

rhuarc30

Your dyno guy was probably right on the money, that 383 will be an air hungry ba***rd, especially at higher rpms, the LTR will have trouble. Plus from what I've seen of the vortec tpi intake I haven't been real impressed, believe the dyno tests they post show a 40 hp gain, well you should see that from just the heads. Got another question for you though, have you optimized your chip? The stock chip will be nowhere near adequate for your fuel, airflow, and spark tables. The siamesed runners will help, I'd check out siamesing that intake as well, or at least porting it substantially. But the first thing would be chip optimization. Hot rod did an article on a tbi 383 a few months back and showed huge gains once they got the programming on the chip right, most of it in the upper rpms. Good luck.
John

PF Flyer

Greg, some of the guys from the Mid Atlantic F-Body Assoc are trying to setting up a Dyno session in Del, if your interested.

Here's the link with the info.

Mike Crews

Hey John (rhuarc30),

Thanks for the response. I do currently have a custom chip from Dean at Street & Performance. I'm on my 6th version of the chip, and I'm pretty sure that we have it dialed in by now. It took about 3 months to get the chip right (and Dean did a great job and was easy to work with). I'm going to approach this from an airflow standpoint to try and get my hp up. Like I mentioned before, I'm going to AS&M SS runners, I'm also going up to 1.6 RRs on my intake valves (leaving exhaust at 1.5), and I'm considering extrude hone for my SDPC intake, or at least doing some serious porting on it (but I probably won't siamese it). I'm also going to get a little more serious on my plenum porting, although I don't know how much more that will help. Hopefully I can get some more airflow. I'll post my new dyno results and track times in about 3 - 4weeks after all my new mods are done.

See Ya, Mike...........

Mike Crews

Oh yea, I did run some of my best times at the track this weekend. I had my best 60' time 1.67, my best 1/8 et 7.94, and my best 1/4 et 12.56. My mph is still hanging around the 106 - 107 range, but I think that the car just doesn't have the hp to do any better that that (only 284 rwhp). The car is only pulling about 21 mph between the 1/8 and the 1/4, so it's just running out of power on the other end. Hopefully I can "fix" that. I can testify that all the money I spent on the Spohn suspension package was well spent, as the car launches awesome. If you're considering any suspension stuff, I can highly recommend Spohn.

Once I get the car running it's best on motor, I'm planning on "experimenting" with nitrous. I have NO experience with it, so it will be a big learning curve for me.

Mike.

steve8586iroc

At what rpm in what gear are you cross the finsh line? Would a gear change help keep the engine in it's best TQ curve, also keeping the rpm's from dropping so much between first and second gear?

Mike Crews

Now I come across the line at about 48 or 4900 rpm with the 3.27. I used to have a 3.70, and I came across at about 5500. With the LTR setup, the car was just "out of breath" at the other end with the 3.70. Just changing the gear from the 3.70 to the 3.27 consistently picked up my mph from 102/103 to 105/106. Every now and then it will hit 107. My 60' time stayed the same with the gear change, so I didn't lose anything there. If I could go a little lower (numerically), like around a 3.08 or so, I think it just might help me some more. But this is not an option with my 9 bolt. I think that I just need to make more hp (more airflow). I don't think that a 106 mph trap speed is too out of line for 284 rwhp. Oh well, just another one of life's mysteries to solve.

Later, Mike..........

steve8586iroc

What type and size off tires are you running?

Mike Crews

I'm running 255/50/16 BFG Drag Radials on stock IROC rims. They hook great at the track, and drive around town pretty good too (as this is an everyday car - sometimes).

Mike....

Kevin91Z

iTrader: (1)

Definitely some puzzling numbers, that HP looks a little low, even for an automatic. Are your heads ported or stock? My dad is putting together a 350 with ported Vortec heads, SDPC base, a ZZ4 cam and SLP 1 3/4" headers. According to Desktop Dyno 2000 it'll make almost as much power as mine! We'll see what happens in a couple months when he gets it done.

Good numbers tho, I'm glad we have a baseline for the Vortec TPI setup now. You're definitely running quicker than I am!

Mike Crews

Hi Kevin,

My heads are pocket ported (bowl blended), nothing too special I guess. They also have stock size Manley valves, competiton valve job, screw in studs, and TPIS springs.

I agree that my low hp numbers are puzzling, but my times are good. I guess it's better to have low dyno numbers with good times (rather than great dyno numbers & bad times). However, that being said, I still have more mods in mind to try and get my dyno hp numbers up. Then I'm going to "spray."

See Ya,

Mike.......

cadence007

Mike, I won't act like I know alot about intakes or anything, but are LT1 intakes known for flowing better then the Vortec TPI's? .. its not that hard of a conversion of the LT1 intake as far as I can tell looking at http://www.lt1intake.com .. then again, maybe I have no idea, and the vortec's flow a hell of alot better.. but I'm guessing the vortec's produce more torque versus horse power, and the lt1's rev higher with better breathing, higher horsepower. Just my 2¢ worth.

Tyler.

Mike Crews

Hey Tyler,

Oh No !!! Not the dreaded question about which intake is better. I'm not prepared to start the "Great Debate", but I will offer my own observations.

I built my engine from kind of a "nostalgic" point of view. I've always wanted a "bad" TPI motor, and I've always loved the way that they look. My engine compartment looks like a brand new 89 IROC - bone stock except for the red plug wires and the jet hot headers. I like the clean stock TPI look. From a performance standpoint, my car runs consistent 12.5s @ 106 at the track. There are plenty of cars there every week with all manner of intakes (and N2O) that can't run a 12.5. My suspension work has paid off big time (my car does not spin off the line), as you are correct about the TPI making big torque. My combination is about perfect for a LTR style setup (IMHO), and you are right about making more torque than hp (just look at my dyno numbers). But my timeslips at the track give me all the real feedback I need.

From a cfm standpoint, I would say that is ould be hard for any TPI style intake to compete with an LT1/Miniram setup (especially as rpm increases). The difference in runner length is simply too great (17 - 21 inches for the TPI vs. 3 inches for the LT1). Theoretically, I would think that my car whould be quicker and faster if I switched to the LT1 intake. For example, I believe that TRAXION went from LTR, to SS LTR, to Miniram, and got quicker and faster with each step. If I was going for performance only, the LT1 intake is obviously a cost effective way to go. Would it be faster at the track - I don't know. Also, I do not believe that the LT1 intake can be modified to fit Vortec heads (someone please correct me if I am wrong). You are also right about the LT1 revving higher and making more hp. Does that guarantee better times at the track - again, I don't know.

Oh well, there it is - my 2 cents to go with your 2 cents (now we have 4 cents - what's that worth ????).

See Ya, Mike..............

steve8586iroc

Mike, what are your cam specs and have you checked you mpg if this car is street driven much?

Mike Crews

Hi Steve8586iroc,

LPE 74211 cam specs - 211 intake, 219 exhaust, 112 LSA, .499/.525 lift with 1.5s, .533/.560 with 1.6s.

My in town mpg is 16.5, and my highway mpg with cruise control at 70 mph is 21.5. I just checked all this last week. Not too bad for what the car is.

Mike...........

1bad91Z

iTrader: (1)

To Mike Crews -

Awhile back, I posted my combo to make ~450hp / 485lb torque. I'm almost done with the motor, probably another couple months (waiting on money for machine work on the heads). But, it should put over 400hp to the back wheels through a 6-speed and it is a LTR setup. If you are interested in my motor's specs, let me know. I could help you bring those HP numbers up. Nice torque #'s by the way!! I'm hoping to run mid 11's (on motor) when I'm done with the motor/tranny swap.

steve8586iroc

Mike, could that be one reason your hp seems low and flat and tqis up and flat as well? That cam is very mild in a 383. I bet you even have a stock idle like 550 to 650 rpm. It seems to match the LTR setup well. I'm just curious if there would be much differance if you were to put the 48mm tb back on. If GM uses it on their 502 ramjet, who knows.

Steve

Pony Killer

I think you have about the perfect Long tube runner set up.
Very street friendly, powerful, and looks to be reasonably easy on gas, not much more you can ask for.

With the Vortec heads, on a 383 they are not going to make much if any more power after 5500rpm, so using the ltr setup is probalby the best thing for it in street trim. If you are looking for any more upper rpm hp out of it, i'd stick with an LTR configuration, and maybe swap the runners and try to sqeeze another 10-15 horsepower up top without sacrificing any of the incredible low and midrange punch it has.

12.5's through a LTR setup is Most impressive, To me it sounds like you have an ideal combination for all around power, ie. maximizing the power in which the heads do their best work, and using a cam, and runner configuration that further will also make the most power in that range... sounds like a well planned project.

84CamroHO

Mike,
211 intake 219 exhaust seems a little mild, that might be your problem. I would call up summit and see what they think. Mybe a cam with 234 intake and 244 exhaust would get the numbers you wanted, or mybe you could go the next one up.

Mike Crews

Thanks for the kind words Pony Killer.

Steve8586iroc and 84camaroHO, I'm pretty sure that you are right about the cam being mild for a 383. I picked the LPE 74211 cam only because Lingenfelter always used that cam in the L98 LTR strokers that he used to build, and I have seen several of those cars run very well. Also, GMHTP routinely recommends this cam (and others) for all manners of LTR setups. I wanted to have a proven good performer when I put a cam in this motor. Cam selection can be a tricky business (especially when you're a beginner like me). I actually have made a few calls to see what type of "bigger cam I could put in, but I hate the thought of going into the motor when it only has 2000 miles on it and is running 12.5s. I do have several cams picked out in the event that I decide to switch. If I did switch, I would never go over 218 intake duration, I'd probably stay around 214 - 216 intake, and about 222 - 224 exhaust. I don't want to mess up a good thing, so to start with, I'm putting on my new AS&M SS LTRs and going to 1.6 RRs on the intake only, then see what that does on the dyno (and at the track). I have a good friend who keeps telling me, "You don't race on a dyno. Did you build your car to get good dyno numers or good track numbers? Leave it alone, it's running great at the track." I'm not sure if I'm going to listen or not.

It's kind of funny, I was perfectly happy with my car until I went to the dyno. Now, suddenly I'm saying that my car is not making enough hp (even though I built the engine with 12.5s as my goal - but I also wanted at least 110 mph). If I had never gone to the dyno, I'd still be content, oh well.

By the way, I did not run the 48 mm TB on the dyno but I did run it at the track. I made 3 runs with the 48, then 3 runs with my 58 mm (I don't have a 52 mm). The car ran consistently .1 - .13 faster with the 58 mm, so I stayed with it.

1bad91Z, you should post your engine specs here on the board so that we all can learn. I'm always interested in seeing what someone has done. That's the best way to see what is working and what is not woking. I'd be very interested in seeing your combo.

Thanks for all the replies guys.

Later, Mike........

MikeH

iTrader: (10)

Very Nice setup Mike, I recently got my new setup running and have been very happy with it so far. I think what you are finding out as I did. This is the typical TPI curve, the horsepower peak looks like the horizon of Kansas.

TPI was made for midrange torque/horsepower, not topend. Makes for a really fun street car, enjoy it!

Mike Crews

Thanks MikeH,

Have you run your car at the track yet? If so, how did it do?

What crank, rods, and pistons did you use for your 406?

Later, MikeC......

MikeH

iTrader: (10)

I havent ran it at the track yet, My wife and I have a 9 month old son. I and cant seem to find the time to go, I have had the car on a chassis dyno. It made 306.5 rwh and 419 rwt, The intake and exhaust are the restrictions right now. I hope to swap out my TES for a better Flowing set within the next couple weeks.

The short block is nothing special really, The pistons are .030 over powerhouse cast flattops. I had the stock rods resized, and I had the stock crank turned .010 under.

Mike, you seem to have your car hooking good with all that torque. I have boxed control arms, and pandard rod, with polybushings. What could I add to my cars rear suspension to help it hook off the line? I plan to use some sort of slick or drag radial for sure.

Mike Crews

Hi Again MikeH,

This is the first project that has required me to mess with any suspension stuff. I really don't know a lot about suspensions. But, my car is a 89 IROC t-top car, and I knew that the car would have serious problems chassis/suspension wise with the new 383 I was building. So, after looking around on the Thridgen board, I decided to call Steve Spohn and ask some questions. He told me (or should I say "sold me") everything I needed to know.

I did everything at once, including lower control arms, adjustable LCA brackets, subframe connnectors, torque arm, and panhard bar. The car rides and drive like a new car. I believe that the adjustable torque arm and the LCA setup are the biggest contributors to my added traction. Also, the SFCs made a big difference in the stiffness of the unibody. I was really amazed at the difference all the suspension work made. My car does not spin at all (I use drag radials too). The car launches like a rocketship (like my 1.67 60' time indicates). Don't know if any of this helps or not.

See Ya, Mike.......

1bad91Z

iTrader: (1)

Hi Mike, my name is Mike also, by the way. 1st off, I'm still impressed with the torque numbers!! However, Horse power is what carries you down the track. The most important thing besides computer tuning in a LTR setep, is the Heads and cam selection. With 17 inches of runner, air velocity to the heads is VERY important. The whole setup from intake through the heads has to flow well with high veloctity. Thats why the mini-ram works so well, "less runner length to rush air through the heads". I stuck with the LTR style intake because I wanted to prove that you can push 400 hp to the rear wheels (naturally aspirated) with a Long tube runner style intake manifold. Right now, you are being limited by your heads. The vortec heads flow decent for what they are (arround 235cfm at .500 lift) thats good for close to 400hp at the crank with a victor jr. intake and 750 holley double pumper. With the LTR setup, you will make more torque than the carb setup, but the carb setup will make 40-50 more ponies at the crank. You will also put more hp to the rear with a manual tranny (you lose more to the rear with an auto). In order to make the kind of horsepower I'm talking about, you need the heads to flow arround 275cfm @.500 and ~280 @ .550 lift on the intake side and ~200 + on the exhuast side. The cam you picked is decent for a 383ci, but you could get more with a cam close to the one I selected. Now, the intake. The vortec TPI intake does flow better than a stocked ported intake, but there is room for improvement. With more air, now you need more gas (Bigger injectors, AFPR to bump up fuel pressure) and then a good ignition system to burn it all. Here are my specs, I hope this helps!


Stock 350 block: bored .030 over, decked at 0, four bolt splayed main caps, toque plate lined honed...........

Stock crank turned and balanced

Trick flow h-beam forged bushed rods (for floating pin pistons)

Lunati forged floating pin pistons (with the heads milled,
= ~11.1 to 1 compression)

Cam: Hyd. roller .536/.544 lift 224/230 duration @.50 112*LSA (specs with 1.6 rockers) Comp lifters and springs (cam kit)

Heads: GM aluminum fastburn heads, ported to 282cfm @.500 lift / 286cfm @.550 lift, changed valves to manley 2.02/1.60 valves with 5 angle valve job, changed springs to match cam (comp)

Intake: Vortec TPI base port matched to heads, runner entries also ported, ported upper plenum (TB ports opened up to 58mm/egr walls milled/runner entries are siamesed), SLP siamese runners (also mildly ported), Holley 58mm billet TB (1050cfm) with coolant bypassed. 26lb injectors, AFPR set to 48 PSI.

MSD ignition: (billet distibutor, 6a ignition box, blaster2 coil, 8.5mm super conductor wires (NGK plugs)

Tuning: www.fastchip.com (custom chip).

Cooling system: Evans cooling system (waterless coolant), edelbrock high flow aluminum water pump. Jet cool fan switch, BE-COOL 3 core radiator with the dual electric fans both wired to the cool fan switch.

Exhaust: 1 3/4in Hooker super comp long tubes (coated 2210's), Corsa 3 in. cat back, custom y-pipe, CATCO 3in high flow cat, 4th gen tips

Tranny: 97 model T-56 6-speed with dual disc Mcleod clutch, pro 5.0 shifter

Rear end: Moser 12 bolt with 3.73 gears

Suspension: All spohn (if I can help it)!! They make good stuff.

And all the current bolt-ons that I have. There are misc. things that I havent mentioned, but I dont want to type forever. If you have any more questions, post them on this topic and I'll help ya in any way I can.

Sorry to bore you guys if I did!!!

Mike

Mike Crews

Hi Mike (1bad91Z),

It looks like you're trying to build a motor to live up to your handle (1bad91Z). It sounds like it's going to be quite a peice of work. I'll be puting on my AS&M SS LTRs this weekend, so I called extrude hone to see how much they wanted to do my SDPC TPI intake since it would be peice of cake to get off while I was replacing the runners. They wanted $365 to extrude hone the intake - ouch!! They say it increases flow 20%. That seems pretty expensive to me. I'm tempted to do a little port work of my own. I didn't do anything to it when I got it, I just bolted it on. How hard was it to do the port work that you did on yours?

I realize now that my cam is fairly mild (I was scared of going too big when I built the motor, I didn't want to overcam the "little vortec heads"). I do have a few cams picked out that I might replace it with, but I am going to wait awhile and see what I can do with this one. I think I can get it into the low 12s with a little more tweaking. Your cam kind of scares me, as it seems a bit too big for a LTR setup, but I am NO EXPERT by any stretch of the imagination (that's probably why I went so small with mine). I'm still learning as I go on a lot of this stuff. Cam selection is certainly one of the most discussed topics on ths board. I was "just looking" at the following cams as potential replacements. Any comments on these?

> TPIS ZZ409 cam (226/226, .520/.520, 112 LSA), too big I think
> LT4 Hot Cam
> Crane HR-276-2S-IG (P/N 109821, 214/222, .488/.509, 112LSA)
> GMPP cam P/N 12370845 (214/224, .488/.509, 112 LSA) very cheap from GM - $218
(Notice how similar the last two cams are.......)

I'd love to hear your comments/sugggestions.

See Ya, Mike.......

1bad91Z

iTrader: (1)

To Mike Crews -

Would you consider spending a little money on your heads before buying a cam? This is what I would do: 1st get a set of valve springs good for upto .550 lift (that way you dont have to buy/install them later if you want to change the cam soon), then take the heads to a good machinist. Have him do a full port and polish, bowl work, ask him if the heads have enough material to punch out for 2.02/1.60 valves, even if they dont, he still might be able to change the seats to fit 2.02/1.60's in them. What ever valve size you end up with, be sure to have a 3 angle valve job done. I would also have the heads milled a little more to bump up compression a little. Now have them flow benched. These are the numbers you need before selecting a cam.

As for the intake, place the upper plenum in a bench vice. Take your siamese runner gaskets, hold them in place against the plenum and use a magic marker to color all the material that the gasket does not cover (in center of gasket etc..). Use a die grinder with a steel carbide metal grinding bit and carefully start grinding away the material that you blacked out with the marker. Repeat the same process for the TB ports using your 58mm TB gasket. Dont be afraid, it's actually pretty easy, just take your time and wear glasses!!!
Now put the lower runner gaskets in place against the manifold. Port intake manifold runner entries using above process. Dont port the intake ports that mate with the heads until you have the heads ported.

Scoggin Dickey performance made 360 HP with an LT-4 hot cam, Vortec TPI intake and ported Iron Vortec heads. I'm not a big fan of the hot cam though.

The cam I have wouldn't be too big for your motor if you have done all the above work. You will need computer tuning though, Ed at (www.fastchip.com) can take care of that for you. You can actually run my cam in a stock TPI 350 if you change the valve springs to handle it and have a chip burned for it, but it is too much cam for stock heads (lift/duration exceeds flow capacity for stock heads) I think stock L98 heads flow peak cfm at ~.450 lift, after that, it drops off.

Anywho, let me know what you plan to do and if you need more help.

Mike :lala:

1bad91Z

iTrader: (1)

Oh yea, and split lift/split duration cams seem to work better in a TPI setup, so I would rule out the TPIS cam.

Mike :lala:

Mike Crews

Hi Again Mike,

Thanks for the reply.

Before I initially put the vortecs on, I had the bowls blended (pocket ported), a competiton (3 angle) valve job, replaced the stock GM valves with SS Manley valves (Tulip stem and swirl polished), and put in TPIS springs with .540 lift. My machinst does a lot of work with vortec heads, and he said that they did not respond well to the larger valves (2.02/1.60), so I opted not to go up on the valve size. He also indicated that he only expected a 10 - 15 hp increase with all the additional work involved in a full port/polish job, and he didn't think it was worth the money. I trust him becase he has always done a great job on all the work that he has ever done for me. He also did the heads on my ZR1. I read the same thing on the Thirdgen board about going up on the cast iron vortec valve size. Anyway, this was supposed to be a "budget" 383, so I was trying to save a little money here and there, but you know how that goes.

So, I figure that my heads are flowing pretty good now (better than stock I'm sure), so I'm not going to pull them. However, I am going to do all the gasket matching and porting for the runners that that you mentioned. I've got a spare plenum that I'll be porting for the SS runners.

Thanks for all your help. I'll let you know how it all turns out. I'm sure that it will be a few weeks before I get it all done.

See Ya, Mike.........

89Raptor

To Mike 1BAD91Z, do you have any dyno numbers or 1/4 times with your setup? Who made your cam? Thanks! Also did you guys hook up the EGR with the vortec intake?

Mike Crews

No EGR on mine - all blocked off.

Mike.......

1bad91Z

iTrader: (1)

89raptor - sorry, no dyno numbers yet, the motor isn't completed (I still need a few parts like custom chip, roller rockers, headers, new valve covers, etc etc......) I'm also going to do the six speed conversion before I put the motor in. I blocked off the EGR stuff (EGR will be turned off in the chip that way it doesnt code) and I will end up removing the smog pump and air tubes when I get the headers. I will definitely will post the dyno results when its all done.

Mike Crews - you should see a difference when all of the intake porting is done. You should talk to Brian at Scoggin Dickey performance. He built a 360hp vortec headed TPI 355ci. I think he used the LT-4 hot cam and the motor still made that much power without computer tuning. He compensated for the bigger injectors by turning the fuel pressure to 31lbs which is 11lbs under the factor setting. With computer tuning, he should be able to crank the PSI to 48lbs and make even more power. Oh yea, and you will get HP gains by doing more porting on the heads and going with bigger valves (about 20 more horsepower at least!) Remember that all of the little things add up.

Let me know how it works out when the motor is back together.

Mike

dlp

Hi Mike, I am currently using one of the cams that you are looking at. The key components of my engine are- zz4 short block, Trick Flow heads, SLP T-Ram intake, 24# injectors, and a crane HR-276-2S-12 IG cam.

Rear wheel dyno summary-
peak HP- 298.1 @ 4900 RPM
peak TQ- 356.8 @ 3500RPM
260+ HP 3900-6000 RPM
340+ TQ 2900-4500RPM

I am still chasing a lean codition problem, these numbers were with an A/F ratio around 14.8/1 above 4500 RPM.

cadence007

Are those 24# injectors enough for that setup? ...

Tyler.

1bad91Z

iTrader: (1)

I think that 24lb injectors will work for him if he had the fuel pressure at 48 to 50 lbs and had a chipped burned for his setup. If his intake porting goes well and he has a chip burned for his car, even with the same cam he has in there, he should be able to put 300 - 310 HP to the back wheels.

89Raptor

1bad91Z - Who made your cam, what part number. Do you need to upgrade to 24 lb. injectors with this setup? I am getting ready to redo my engine next month. I'm going to do a Vortec headed engine but I thought the 22 lb. injectors would suffice. Thanks.

Mike Crews

Hi dlp,

COOL - an SLP T-Ram !!!!! I've only seem those in pictures, never in person. So, I'm assuming that you are happy with your cam (any problems/regrets)?? It looks like you have very good dyno numbers. Are you going to fix your lean condition with your chip, or by increasing your fuel pressure?

Oh yea, have any of you guys put 1.6 rockers on your "regular" vortec heads? I'm wondering if the push rod hole is big enough on my heads (they don't have any modifications to the push rod hole). Will my push rod rub on the stock heads?

Mike.......

1bad91Z

iTrader: (1)

89Raptor - It's a comp cam, I dont have the part number on hand, but I'll get it for you if you'd like. I need at least 26lb injectors for my setup, I'll probably end up going with 28lb injectors though. The 24lb injectors will work well with a setup like Mike Crews' has.

Mike Crews - I dont think you should have any problems with the pushrods when you goto 1.6 rockers, but I would talk to your machinist since he is the one who did your heads. Best advice I can give you is to go with the Comp cams magnum series 1.6 roller rockers (they're the best in my opinion). Next choice would be the Crane gold series narrow body roller rockers. Both sets are on the pricy side though! $$$$

Mike

Mike Crews

1bad91Z - Good advice, that's exactly what I did today. My machinist said that he didn't think they would hit, but I should put one on and check just to be sure. I bought a set of used (2500 miles) comp cams magnum 1.6 roller tip rockers from a guy on the board. I'm going to give those a try, as I'm using stock valve covers (maintaining the all stock look). I'm only going 1.6 on the intake. I'm staying 1.5 on the exhaust.

I still need 8 1.5 roller tips to go the exhaust (I'm still running the stock stamped steel rocker arms). If anybody has 8 1.5s, I'll buy them or trade 8 1.6s for 8 1.5s (must be self aligning).

Later, Mike........

89Raptor

If it's a comp cam I can get the part number of my camdisk so I can plug it into desktop dyno, thanks.

1bad91Z

iTrader: (1)

Mike Crews - Do yourself a favor and use 1.6's all the way arround!! The only reason that I would even consider using 1.5's on the exhaust side would be if my valve springs couldn't handle the cam lift that the 1.6's would raise it to. And, it that was the case, I would just upgrade the springs.

89raptor - I plugged all my specs into desktop dyno 2000. The numbers it gave me were a little low. It said that I would only make 434 hp / 485 lbs torque. Remember, desktop dyno can't accomidate for factoring in the intake porting and custom computer tuning (all which add ponies). I could e-mail you the Desktop dyno 2000 motor file if you'd like.


......Mike

89Raptor

Mike shoot me that file so I can check it out!
Thanks!

Pony Killer

I Guess i'm of the Opinon that What you've got is Very Very good, and dont' see a real need to change it drastically especially since it seems from here that it sees a lot of street use. My advice would be to just massage the intake, nothing drastic whatsoever, and Tune it as best you can, and See where it gets you. The Times your running are very impressive.

There's No need to go sacrificing 20-30lbs of midrange torque from3000-5000rpm, to get 15hp at 5500rpm. Most likely the car will be slower. as said somewhere else problaby.. you don't race on dyno's, you'r peak power's not what gets you down the track.
Tune it and tweak it to get the most power out of the broadest part of your powerband, and see where that gets you before you go sliding camshafts and intakes on it.

With tuning, and nailing everything down you could most likely get another few tenths out of it.

Mike Crews

Hey Guys,

I'm going with 1.6s on the intake and not the exhaut for two reasons. First, with 1.6s on my exhaust I'll be at .560 - way overkill for vortec heads I think (far past the stall point even for ported vortecs). Second, messing with my exhaust port now will likely cost me torque that I don't want to give up. My dyno run data tells me that my car is having trouble getting air - not getting rid of it. And I agree with you (again) Pony Killer, I don't want to mess up a good thing, so I'm not even considering a cam change anymore. I'm going to do the swap to the AS&M SS LTRs, and add the 1.6s on the intake. The results will tell me what I need to know (good or bad). I'm hoping that the combination of the increased lift and the SS LTRs will help the car to get air a bit easier, which should result in more hp with no sacrafice of torque (it always sounds so good in theory). If things don't pan out, then I'm going back to my original combination. I'm also hoping that you're right about getting a few more tenths out of my final tuning and tweaking.

Later, Mike.........

FlashGTA

Mike any updates?

Mike Crews

Hi FlashGTA,

As a matter of fact, I spent Friday and Saturday taking the top end of the car part, painting the AS&M SS runners (Lingenfelter ZR1 gray), and porting/painting my spare plenum to match the SS runners. All that stuff is ready to go back on. The SS runners with the plenum ported to match looks like it is going to flow like crazy. I took so much material out of the plenum, there can't be much restriction to flow there anymore. I have high hopes for those pieces.

Also, I took my valve covers off and have installed one of the intake 1.6 roller tip rockers. I'm looking at how close the push rod is to the hole in the head. It's pretty close, but it's not touching. My heads do not have the modified push rods holes. I slept on that last night to make sure that I didn't make a hasty decisison that I'll regret. I'm also gong to ask my neighbor today (he's a GM mechanic for on of the local dealers). Once I get that done, I'm going to the dyno this Friday afeternoon to check everything. I'll post the results.

Flash GTA, I see that you have Crane rollers. Are they 1.6s? Do your vortec heads have the elongated push rod hole?

Is anybody out there running 1.6 rollers (or roller tips) on vortec heads without elongated puch rods holes?

Thanks, Mike......