Dynoed my car tonight ant the numbers were extremely disappointing!!!I've heard of 355's laying down better numbers with stock castings!!! I have AFR 195's, CC306, all the boltons,etc(all mods on car domain link). the air fuel ratio looks good and the car runs great. Throttle response is great, pulls hard everywhere and no stumbling or surging at any RPM....what gives....i think i should at least have 400rwhp and 400rwtq with this setup!!!
Dyno Graph

Chart


Mods
Block: .030 LT1 2 Bolt, clearanced for 3.875 stroke
Compression ratio: 10.7
Heads: AFR 195 LT4 70cc chambers, w/Comp 987 springs
Cam: Comp Cams 306 (230/244 at .050) (.544/576 lift, 112 lsa)
Pushrods: Trick flow chromemoly one piece
Roller Lifters: Comp Cams Comp R
Rocker Arms: Harland Sharp Roller Rockers 1.6 ratio
Pistons: SRP forged Alum. -5cc
Crank: 3.875 Eagle Forged
Rods: 6in Eagle H beam
Throttle Body: BBK 58mm w/K&N cold air induction kit,descreened and ported MAF
Intake: Edelbrock LT4
Water pump: CSR electric
Motor mounts: energy suspension polyurethane
Fuel injectors: Ford racing 30pph
Fuel pump: Walboro 255lph
Ignition: Stock, Stock Optispark, MSD blaster coil and wires
Engine management: Stock PCM,LT4 Knock Module
Exhaust: Pacesetter 1.75in long tubes, off road y-pipe, stainless works chambered muffler, SLP quad center exit exhaust

I'm tempted to go to another dyno shop to get a second opinion.....since the guy tuning told me repeatedly the heads and cam weren't big enough....is he right or full of BS?????

 

Those numbers are low. What CCs are your 195s for your combustion chambers. You may have a low dynamic compression if you are using 64cc heads.

 

yes...all the data logging according to him looked good and there was no knock retard.

 

Who tuned your car?

 

More compression wouldn't hurt, the cam leaves a lot on the table also. Not a big fan of the 987's either they seem to lose control in the 6000+ range depending on the cam of course. Who ported the heads, what do they flow?

 

the heads have 70cc chambers....AFR Street porting

 

The heads and cam are choking your motor, with that aside it should make more power than that. And that muffler isn't helping you either, it necks down to 2.5".

 

First problem I see is low compression. Second not enough head flow for the needs of a 396. Is your intake manifold ported?

 

well i kept the compression lower so i coudl run 91oct without any problems. the edelbrock intake isn't ported. there didn't seem to be any mismatching either(TB bores or runners), so i didn't mess with it.. I agree the muffler is a POS, the more i drive it the more it annoys me... its going to get changed. i want the car to be a steetable with occasional road course abuse. i thought the 195cc AFRs would be prefect for a street car, instead of the 210's....What cam should i have used then???? At this point i'm tired of tearing the thing apart.....i might swap cams but that would be all i'm willing to at this point. Its taken so long ot get to this point, that i really want to just enjoy the drive the damn thing

 

The 195's are rated to flow on strokers. I doubt they are what's causing you power. Is your intake port matched to the heads yet? THat's the key to getting the most out of th ose AFR's, and why are they only reving your car to 6400. With that setup you should be taking it much higher. I would ditch that cam, and get something custom that will get the most out of your setup.

 

I think that you have a bunch of mismatched parts. The heads are probably okay, but the 210's would be better for that many CI. Also the cam is very small for a stroker. I would get a custom ground cam and go from there. BTW a bump in compression would help. I'm running well over 12.1 on 93 octane.

 

What is "AFR Street porting"? Are you saying they are AFR 195's "as cast" with no porting at all?

My assumption is they have no porting from your description and "as cast AFR 195's" are not "stroker rated" and do not flow well at all without porting. You would have been much, much better off spending the money on porting stock castings instead and have gotten something for your money. Never ever heard that term (stroker rated) used before even to describe as cast 195's. Stroker LTx motors respond better to the larger cross section of a 210-220cc head.

If they are not ported, that along with the 70 cc chambers would be the first thing I'd look at. You need more compression for better performance and LTx engines love compression. The 306 cam works better in a stock block than in a stroker and it would be the next.

No experience with the intake but I'd be skeptical that it also doesn't need a bit of clean up work to get the most out of it. On a stroker motor welding excess material just above the injectors so you can straighten out the path and not run out of material is worth 10 hp.

Your dyno sheet looks very clean not looking like anything is wrong. Just doesn't appear to be getting a lot of air in and out to make the power up at higher rpm. Check your air induction by disconnecting it at the MAF next time you dyno to make sure it isn't an issue and I'd also dissconnect the Y-pipe to make sure the rest of your exhaust isn't an issue.

 

The LT4 195/210 series are rated for strokers. With his street competition port he hsould be good on the heads. The problem is if he doesn't have that intake matched he's leaving allot of HP on the table with those heads. I'm not sure how large the ports on the Edelbrok LT4 intake are, but if they are anything like the stock GM lt4 ports... time to grind.

 

I'll go out on a limb and say the 306 is not hurting him like most believe. That cam should make well over 400rwhp with all else working fine on this engine. That is not to say that the cam and heads are matched okay - there is something up with the heads, and I agree they are too small for max power, but it still should be making more than it is. That thing is sucking vacuum and/or the rocker arms are too tight, and the compression is too low.

 

I would say "more compression" to start with! With 70cc chambers your comprssion is probably around 9.5 to 1, or less.

My AFR 195 LT4 heads have 58cc chambers. Therefore with the 0-deck height, flat top pistons and .039 headgasket I have about 12.2 to 1 static compression to start with. I'm also running the Comp XFI-292 cam which I've been very happy with.

WD