468ci with PI 275 heads/Harrop itb-- 710hp, 680tq--missing power?
09-01-2010, 04:39 PM
#41
TECH Apprentice
Thread Starter
iTrader: (1)
Join Date: Oct 2006
Location: NJ
Posts: 374
Likes: 0
Received 0 Likes
on
0 Posts
Yep I see and deal with this almost every engine that goes out to anyone else to tune. It's a compromise and I agree with nearly all the advice Shawn gave Roberto except we never run as much as compression as other shops do and that's part of the reason we probably still have the reputation we do.
Roberto's deal power to weight at 700 hp at only 6000 rpm is enough to run into the 8s and over 150 in the quarter which is quite a lot for a 6500 rpm hydraulic roller pump gas deal that should last a good long time. The bigger inches and Harrop both make for outstanding lower rpm and midrange power and still some decent top end in reality.
Roberto's deal power to weight at 700 hp at only 6000 rpm is enough to run into the 8s and over 150 in the quarter which is quite a lot for a 6500 rpm hydraulic roller pump gas deal that should last a good long time. The bigger inches and Harrop both make for outstanding lower rpm and midrange power and still some decent top end in reality.
Thanks for adding to the thread Erik.
Rob's car was making around 700+rwhp with the Harrop last year. Although the harrop is not the ideal drag race manifold and high rpm manifold it surprisingly works quite well and you can't beat it's street manners.
Harrop has not update their design. Larger diameter trumpets would be better for bigger cubed motors for sure and a taper couldn't hurt but we really feel the Harrop is not the choke point here. As Ed H. knows, the Harrop needs to be ported alot to help line up with heads and strighten out runner. IMO there are several intrinsic problems with all of the mITB manifolds out there but that's for a different discussion. It's hard to please all buyers and that's why we have custom intakes.
The harrop seems like a great choice for RR and can tame a big cam making it very driveable.
To the owner: I'd drive it and race it in it's current configuration because at that weight the car will be a rocket and you might not want more power. You have a great team behind you.
Harrop has not update their design. Larger diameter trumpets would be better for bigger cubed motors for sure and a taper couldn't hurt but we really feel the Harrop is not the choke point here. As Ed H. knows, the Harrop needs to be ported alot to help line up with heads and strighten out runner. IMO there are several intrinsic problems with all of the mITB manifolds out there but that's for a different discussion. It's hard to please all buyers and that's why we have custom intakes.
The harrop seems like a great choice for RR and can tame a big cam making it very driveable.
To the owner: I'd drive it and race it in it's current configuration because at that weight the car will be a rocket and you might not want more power. You have a great team behind you.
Va Speed ported the Harrop for me. As far as I know, it's ported as much as it can be ported. When the car and engine are back in Jersey I would like to come with you guys to a track day. I just picked up a transaxle last night that should have no issues holding this torque with sticky tires on a semi-hard launch. I'm not sure how the gearing ratio's of a Porsche 997 (11 TT gear box will pan out with 26" tires....but we will see what it'll do regardless. Interestingly the Porsche 911 TT peaks at the EXACT same rpm as my motor does. 5k for torque, and 6k for hp and the Porsche has a 6600rpm redline. In fact with it's variable vane turbos it makes close to peak torque below 2k rpm and carries it about flat to 5k. Insane.
Thanks for the advice...it's very sound. I should probably enjoy it as is. The car will be a death trap as is. But we are all in this hobby to get the most we can within our combo's tolerance, and respective budgets. lol Otherwise we would all be driving factory spec cars.
09-01-2010, 04:46 PM
#42
TECH Apprentice
Thread Starter
iTrader: (1)
Join Date: Oct 2006
Location: NJ
Posts: 374
Likes: 0
Received 0 Likes
on
0 Posts
The reason I created this thread was for feedback on the results considering the combo from people with more experience than me. I admit to being slightly disappointed at the 710hp # when I initially heard it, but again I wasn't sure if I SHOULD have any disappointment considering the combo/constraints placed on the build (Harrop, streetable, pump gas, reliable).
In fact the more I've read, learned, and spoken to people about it, I'm actually happy with the results. Going into this I really didn't know what to expect #'s wise as it hasn't really been done. I allowed myself to get caught up in the #'s game of people running a point or more of compression, much larger cams, different intakes, etc a little bit too.
Would I like more hp? Of course, who wouldn't...the nice thing is more hp is a manifold and/or cam swap away.
Regardless of peak #'s moving the powerband to the right may make the car slightly easier to drive fast though.
I appreciate people's thoughts and opinions on the combo, as well as sharing their experiences. I've gained some helpful insight.
Even more I appreciate Erik's humility (as well as the bad *** engine he built) as I spoke to him first before posting about the engine/cam specs, etc. He had zero issue giving out cam specs, nor posting/discussing on the internet about the combo/results. He is not only the best engine builder in the biz, but a downright good guy. Not too many in this hobby unfortunately. He isn't the fastest builder, lol...but he's made a customer for life.
In fact the more I've read, learned, and spoken to people about it, I'm actually happy with the results. Going into this I really didn't know what to expect #'s wise as it hasn't really been done. I allowed myself to get caught up in the #'s game of people running a point or more of compression, much larger cams, different intakes, etc a little bit too.
Would I like more hp? Of course, who wouldn't...the nice thing is more hp is a manifold and/or cam swap away.
Regardless of peak #'s moving the powerband to the right may make the car slightly easier to drive fast though.
I appreciate people's thoughts and opinions on the combo, as well as sharing their experiences. I've gained some helpful insight.
Even more I appreciate Erik's humility (as well as the bad *** engine he built) as I spoke to him first before posting about the engine/cam specs, etc. He had zero issue giving out cam specs, nor posting/discussing on the internet about the combo/results. He is not only the best engine builder in the biz, but a downright good guy. Not too many in this hobby unfortunately. He isn't the fastest builder, lol...but he's made a customer for life.
Last edited by Stage7; 09-01-2010 at 04:55 PM.
09-01-2010, 04:51 PM
#43
TECH Apprentice
Thread Starter
iTrader: (1)
Join Date: Oct 2006
Location: NJ
Posts: 374
Likes: 0
Received 0 Likes
on
0 Posts
The manifold choice wasn't really about power, but rather driveability. They have the ability to calm bigger cams. Doesn't hurt that they look great too.
Everyone involved would like to see it make more power, but I don't think the owner wants to make more power at the expense of driveability.
Everyone involved would like to see it make more power, but I don't think the owner wants to make more power at the expense of driveability.
Last edited by Stage7; 09-01-2010 at 05:44 PM.
09-03-2010, 12:07 AM
#44
TECH Apprentice
Thread Starter
iTrader: (1)
Join Date: Oct 2006
Location: NJ
Posts: 374
Likes: 0
Received 0 Likes
on
0 Posts
Well, Ed is about finished the itb adjustments, and idle/drivability tuning on the motor. It's idling at 800rpm, just about dead smooth according to Ed. He is going to send some pix, and try and get a short video clip of it idling.
